Contents Of This Website


Physical and Psychological Effects Of Hypospadias 
by Dominique Salm, 2003

Chapter 1: General information about hypospadias (This page is chapter 1)

Chapter 2: Hypospadias and surgery
Link to chapter 2
Chapter 3: Psychological, social and sexual perspectives Link to chapter 3
1. Introduction
2. Some definitions
2.1. Etymology
2.2. Current definitions
2.3. Specialist definitions
3. Embryological origins of hypospadias
3.1. Normal sexual determination and differentiation
3.2. Hypospadias : embryogenesis
4. Anatomical considerations
4.1. General anatomical characteristics
4.2. Associated anomalies
5. Diversity and classification of types of hypospadias
5.1. Hypospadias or intersexuality?
5.2.Variations of hypospadias
6. Etiological hypotheses of hypospadias
6.1. Hereditary factors
6.2. Genetic factors
6.3. Endocrinal factors
6.4. Environmental factors
7. Epidemiology
7.1. Frequency
7.2. Incidence
8. Conclusion
1. Introduction
2. Consequences of hypospadias
2.1. Functional problems
2.2. Aesthetic repercussions
3. Objectives and principles of surgery
3.1. Objectives of surgery
3.2. Principles of surgery
4. Surgery for hypospadias : historical view
5. Preferred age for surgery
5.1. Some changes to retain in the timing
5.2. Current practice
6. Some technical aspects of 'hypospadiology'
6.1.Correction of chordee
6.2. Urethroplasty
6.3. Reconstruction of the ventral side of the penis
7. Possible complications
7.1. Urethral fistulae
7.2. Stenosis of the urethral meatus
7.3. Persistent chordee
7.4. Unsatisfactory aesthetic results
7.5. Multiple failures
8. Pre-admission and post-operative care
9. Conclusion

1. Introduction
2. First series of studies  (Sweden, 1980s)
2.1. Aspects studied
2.2. Sample studied
2.3. Principal results
2.3.1. Delays in psychosexual adaptation
2.3.2. Psychological and interpersonal disturbances 
2.3.3. Doubts regarding masculinity
2.4. Implications of the data
3. Second series of studies (The Netherlands, 1990s)  
3.1. Aspects studied
3.2. Sample studied 
3.3. Principal results
3.3.1. Perception of genitals: different and more negative
3.3.2. Psychosexual inhibitions
3.3.3. Lack of guidance and communication
4. Synthesis of 2 studies
4.1. Paucity of literature
4.2. Offering professional psychological support 
4.3. Another risk factor: the hypospadias secret
5. Qualitative research (USA, 1998) 
5.1. Subjects investigated
5.2. Research method used
5.3. Research participants
5.4. Some results
5.4.1. Lack of emotional support
5.4.2. Feeling different and keeping hypospadias secret
5.4.3. Feelings of embarrassment 
5.4.4. Shame and poor self esteem
5.4.5. Anxiety and fear around sexual intimacy 
5.4.6. Solitude, isolation and mistrust
5.4.7. Feelings of loss and incomplete masculinity 
5.4.8. Personal growth, acceptance of self and body 
5.4.9. Support from other men with hypospadias 
5.4.10. Hypospadias as part of life's experience
5.5. Implications of the research findings
5.5.1. Implications for professionals 
5.5.2. Implications for family members
6. Synthesis of the study and links with literature 
7. Conclusion
Articles referenced
Internet addresses of medical papers


This is a theoretical research paper on the psychological consequences of hypospadias, a male congenital deficiency of the urethra.  The term hypospadias refers to the urethral meatus, or opening, which instead of being located at the tip of the penis is found somewhere along the ventral side of it.  There are different degrees of severity of  hypospadias.  In the least severe cases the urethral opening is located just below the glans of the penis; in the most severe cases the opening is found at the base of the penis close to the perineum.

The vast majority of literature concerning hypospadias is found in the medical domain, primarily in surgical and pediatric urology, but also in the field of endocrinology.  Hypospadias is one of the most common congenital malformations in boys and men, and consequently there are a great many articles which discuss its correction by surgery as well as its physical etiology. 

My interest in approaching the subject of hypospadias in a psychology thesis stems, in part, from the fact that there is hardly any data on this issue in French literature in the area of human sciences, and the field of psychology in particular.  My objective is to contribute a modest advancement in this field.  Since we know that hypospadias affects almost one man in 300 - according to the latest estimates - it seems important to explore the possible reasons for the relative silence surrounding the condition.  And since hypospadias affects one of the most personal parts of the male anatomy,  how could it not have psychological repercussions?  How could this condition only relate to the physical aspects?  As a future psychologist, it seems very relevant to me to explore these questions more deeply.    

In all honesty, however, even before commencing this research I had some idea of the kind of answers which might be found in answer to these two questions.  Being personally affected by the issue, I'm already aware that hypospadias is a psychological condition as well as a physical one, and that it is not easily approachable.  The difficulty in finding information about hypospadias, along with the lack of opportunities for discussing it, has for many years left me perplexed. For a long time I have been asking myself not only what the causes of hypospadias could be, but also whether I would ever have the opportunity to meet other people in the same situation.

I must add that as well as trying to find articles or research studies on the consequences of hypospadias, my approach has been towards lifting the veil which conceals this condition. And the title of this thesis tries to reflect how much men with hypospadias wish to better understand the impact of hypospadias both on ourselves and on others. You may wonder why a psychology thesis with these aims comprises two chapters on the medical aspects concerning hypospadias and only one chapter concerning its psychological, psychosocial and psychosexual consequences. I believe it's extremely useful to offer people with little knowledge of the subject some information on the various data available - embryological, anatomical, etiological and epidemiological - and also some information on the surgical treatment of hypospadias.  Why is this?

First, the medical aspects of hypospadias represent the greater part of the available literature. And the medical literature can be very useful, for example in better understanding the origins of hypospadias.  In recent years, many epidemiological and eco-toxological studies have suggested that hypospadias might be increasing in many industrialized countries. There may be a link to our modern lifestyle, particularly to many forms of environmental pollution, which may influence vital hormonal processes such as the production of male hormones (androgens) during the embryo's sexual differentiation, contributing to the malformation of the external male sex organs. 

Second, as well as helping us to understand the etiology of hypsospadias, the medical literature describes the physical consequences of hypospadias and the effect it has on urination and sexual activity.  I regard it as important to review work in the fields of pediatric urology and surgery to see which surgical techniques have been adopted as best practice in this field, and to consider both the resulting quality of surgical reconstructions of the urethra and the psychological impact of this type of surgery. 

This thesis is divided into three chapters.  The first chapter presents some general reflections on hypospadias, the second chapter reviews the issues around surgical treatment of hypospadias, and the third chapter is devoted to the psychological, psychosocial and psychosexual issues associated with hypospadias.  

In the first chapter I start by defining hypospadias, and then present data related to embryology, anatomy, medical classification, and the etiology and epidemiology of hypospadias. 

In the second chapter, I discuss the surgical treatment of hypospadias.  I consider the the objectives and principles of surgery in this field and review the physical consequences of such surgery.  I also present a historical review of hypospadias surgery.  In addition, I explore the issues surrounding the optimum age for surgery, surgical techniques currently utilized, inherent complications in this type of surgery and finally, pre- and post-operative care.  

In the third chapter, I present three psychological studies on hypospadias.  Two of these are quantitative in nature and one is qualitative.  After reviewing the focus of these studies, I consider the principal results and the implications of this research for people with hypospadias and their families.  

Chapter 1: General considerations about hypospadias

1. Introduction

The first chapter of this thesis presents a selection of knowledge and discoveries concerning hypospadias drawn from medical research across several disciplines.  Initially, however, I present several definitions of hypospadias drawn from both normal and more specialized dictionaries: some aspects of these definitions will be considered in more detail elsewhere in this thesis.  Next, I review the embryological development which leads to formation of the genito-urinary tract, with particular emphasis on the development of the male fetus; this serves as a background to the embryological origins of hypospadias.  Then, I review the anatomical aspects of hypospadias and describe the various forms it can take. As we shall see, the diversity of hypospadias has resulted in the creation of special classification systems.  In addition, I have approached the question of the etiology of hypospadias.  To this end, I propose a joint view of the principal etiological hypotheses to be found in literature, taking into account many possible factors: hereditary, genetic, endocrinal and environmental.  Finally, the first chapter ends with some epidemiological data on hypospadias, which demonstrates the frequency and incidence of this condition.

2. Some definitions 

2.1. Etymology

Etymologically, the term hypospadias is derived from the Greek hupo, meaning 'under' and  spaô, a 'fissure' or  'crack'.  

2.2. Everyday Definitions

Firstly we can note a few definitions from different everyday dictionaries.  The definition of hypospadias given by Le Petit Larousse (2003), is relatively short: Malformation of the penis in which the urethra opens on the inferior side and not at the extremity.'  Le Petit Robert (2003), defines hypospadias as follows: 'Malformation of the urethra, characterized by a urinary meatus situated on the inferior side of the penis or even at the level of the perineum.

2.3. Specialized Definitions 

Other more specialized dictionaries also offer us information as to the meaning of the word.

The Dictionnaire des Termes de Médecine (Garnier & Delamare, 2000) gives an anatomical definition: Malformation of the male urethra, characterized by the division, to a greater or lesser extent, of the inferior wall, with an abnormal orifice situated at a variable distance from the extremity of the organ.

The definition from the Larousse Médical (2003) seems more descriptive : Congenital malformation in which the urethral meatus (external opening of the urethra) is situated on the inferior side of the penis.  A malformation of the prepuce, absent on the anterior side is always associated with hypospadias.  The urethral meatus may open at different levels of the urethra.  Hypospadias is known as glanular when it opens under the glans, penile when it opens in the middle of the penis and peno-scrotal when it opens at the junction of the penis and scrotum.

In Le Dictionnaire des Maladies, for the use of health professionals (Prudhomme & d’Ivernois, 2002), still more information can be drawn from the definition: Malformation of the urethra, very common (affects one boy in 300), characterized by a malpositioning of the opening of the urinary meatus which is situation further back on the glans, on the inferior side of the penis or at the junction of the penis and scrotum.  Chordee is often associated.  Treatment is surgical and gives excellent results. 

Most of the knowledge about hypospadias resides in the specialized medical field of surgery and pediatric urology.  I quote, for example, the definition offered by De Sy & Hoebeke (1996, p.158) : Congenital anomaly of the penis which results in an incomplete development of the anterior urethra.  A hypospadias is characterized by the degrees of deficiency of the urethra and of the corpus spongiosum and the corpus cavernosa.

I will expand the various aspects of hypospadias implied in the above definitions through a review of the medical literature on hypospadias.  I will center my subject matter on the many relevant elements, namely: the embryogenesis of the penis and urethra, anatomical knowledge of hypospadias, etiological hypotheses, epidemiological data and treatment by surgery.

3. Embryologic origins of hypospadias 

Hypospadias may be considered as a relatively common malformation of the male genito-urinary organs (Hencha-Razavi & Escudier, 2000). It is caused by arrested development of the urethra during the period of embryological sexual differentiation (Larsen, 1996).  To better understand this, I shall review some principles of embryonic sexual differentiation [1], the process which leads to development of the genito-urinary tract in humans.  I will pay particular attention to this development in the male.  To do so, I will refer to Hugues (2001, p. 3281), for whom the process of sexual differentiation can be defined as  'phenotypic development of the internal and external genital structures, under the action of hormones which have been produced following the determination of the gonad'.

3.1. Normal sexual determination and differentiation: a recap 

The differentiation of the gonad (which at the beginning of the process is the same in both sexes [2]) into a testicle or an ovary is a genetic process known as sexual determination (Hugues, 2001). The factors responsible for sexual determination are partly chromosomal and partly at the level of the gene (Hencha- Razavi & Escudier, 2000). At the moment of conception the sex of the embryo is determined by the combination of sexual chromosomes: in males, the chromosomal sex is most often 46 XY, in females 46 XX.  In addition, there is a specific gene sequence responsible for testicular development.  It appears that the gene SRY [3], carried by the Y chromosome, is the principal initiator of the cascade of genetic interactions which determine the development of the undifferentiated gonad into a testicle [4]. As for the term gonadic sex, this is used to describe the status of the gonads: whether they comprise testicular tissue, or ovarian tissue.

Following the gonad's determination as a testicle, masculine sexual differentiation is dependent on the production and action of androgens - hormones of gonadic origin (Hugues, 2001).    

Until the sixth week, whatever the sex of the embryo, the internal genital passages are represented by two pairs of genital canals: the Wolferian and Müllerian ducts.  These ducts take one or other direction according to the hormones produced by the gonads (Hencha-Razavi & Escudier, 2000).  In male embryos (46 XY), the internal male phenotype is achieved thanks to the secretion and action of two androgens.  One is the anti-Müllerian hormone (AMH) which permits a regression of the Müllerian ducts. The other is testosterone, which contributes to the maintenance  and development of the Wolferian ducts (epididymis, vas deferens, seminal vesicles and ejaculatory ducts [5].)   

The constitution of the external male phenotype sex (external genital organs and genito-urinary sinus) needs the conversion of testosterone into a more powerful hormonal derivative - dihydrotestosterone or DHT - which happens with the help of  a specific enzyme, type 2  5-alpha-reductase (Hugues, 2001).    

To recap, the external genital structures develop in both sexes (46 XY or 46 XX), from the same original tissues.  In the state known as undifferentiated (Hencha-Razavi & Escudier; Larsen, 1996), these tissues are identical and comprise a pair of labio-scrotal folds, a pair of genito-urinary folds and a genital tubercule (see Figure 1).    



FIGURE 1 Source : Larsen (1996)

Normally, in an individual of male genetic sex (46 XY), between the 8th and 14th week the genital outlines change under the influence of DHT which fixes itself on special cell receptors (Larsen, 1996). On one side the pads of genital tissue knit together to form the scrotum.  On the other, the genital tubercule elongates to form the shaft and glans of the penis.  As the penis grows, the genital folds are drawn forward, then knit together under the penis.  During this process of knitting together the genito-urinary membrane forms the urethral canal, which, in fusing, forms a tube the whole length of the penis, comprising the penile urethra.  

This process continues forward and draws nearer the glans: this is the glanular urethra.  The extremity of the glans, containing the most distal part of the urethra, is formed through an invagination of epithelial cells hollowing out the centre of the glans.  Finally, the urethra opens at the extremity (or apex) of the glans in a vertically oriented slit (see Figure 2).  The formation of a complete prepuce (foreskin), with its final cutaneous fold surrounding the glans on its ventro-dorsal part, signals the successful end of this process.  


  FIGURE 2 Source: Larsen (1996)  

In the absence of androgens and DHT, the external sex organs differentiate in the female way (Larsen, 1996). The genital tubercule inclines towards the base to form the clitoris, the genito-urinary folds remain separated to form the small lips (labia minora) of the vulva, and the labio-scrotal folds do not knit together and consequently form the large lips (labia majora).

3.2. Hypospadias: embryogenesis

Different manifestations of hypospadias can appear, depending on the moment when, during the embryonic development of the phenotypic masculine sex, the different fusion processes which form the urethra are disrupted (Larsen, 1996). According to Frisén (2002), the severity of hypospadias can be seen as a continuum. The earlier the fusion process is interrupted, the hypospadias will be classified as 'severe' or 'complex'.  Conversely, 'simple' cases of hypospadias will arise from failures during the terminal phases of urethral development.

The degree of hypospadias depends on the location and the length of the urethral orifice (Larsen, 1996). The most severe cases of hypospadias arise when the pads of genital tissue do not fuse at all.  The urethra opens in the perineum and the hypospadias is called 'perineal' [6]. In the case where the genital pads fuse only partially, and the urethral orifice opens between the base of the penis and the root of the scrotum, the hypospadias is classified as 'peno-scrotal' (see Figure 3). 


FIGURE 3   Source: Larsen (1996)


An incomplete fusion of the genital folds produces an opening of the urethra at a point along the ventral side of the penis, which is 'penile' hypospadias (see Figure 4).      

FIGURE 4  Source: Larsen (1996)  

Finally, when the epithelial invagination of the glans is defective, the urethral opening is located under the glans, and this is known as 'glanular' hypospadias (see Figure 5).


FIGURE 5  Source: Larsen (1996).

The conditions described (Larsen, 1996), represent the four major forms of hypospadias likely to be encountered.  However, as we shall see, numerous anatomical varieties of this condition are possible.

4. Anatomical considerations 

As already outlined, the term hypospadias refers to the position of the genito-urinary orifice - the urethral meatus - when it opens somewhere along the path of the urethra (Wese, Opsomer, Abi-Aad et al., 1994). To recap, in a man the urethra is a canal in the form of a tube which runs the whole length of the penis and opens as a hole or slit positioned at the end of the glans. The primary functions of this tubular structure are to carry urine and to allow the passage of semen (Tortora & Grabowski, 1994).

4.1. General anatomical characteristics

Three anatomical characteristics have traditionally been associated with hypospadias (Paparel, Mure, Margarian et al., 2001), as follows:  

-       an ectopic urethral meatus

-       an incomplete prepuce 

-       chordee

The unusual placement of the urethral meatus is a reliable anatomical characteristic of hypospadias. Hypospadic urethral openings may be located at a variable distance from the extremity of the glans. This ranges from a slightly displaced orifice under the ventral side of the glans to an orifice located in the perineum.   

The incomplete prepuce refers to an excess of preputial skin on the dorsal side of the penis which is absent on the ventral side [7]. (This appears as a hooded foreskin covering the dorsal half of the glans only.) This characteristic regarding the prepuce often accompanies hypospadias but is not always constant [8].     

The term chordee refers to the existence of a ventral curve of the penis, especially noticeable during an erection.  In general, the extent of chordee is relative to the degree of hypospadias.  

In the last few years, some specialists (pediatric urologists) have opted for a more anatomical approach.  Thus, as per Paparel et al (2001, p. 741), hypospadias can be defined as a 'hypoplasy of the tissues forming the ventral side of the penis'. Anatomically, a penis known as hypospadic is characterized by an immaturity of the tissues (hypoplasy) situated on the inferior side of the penis: those forming the urethra, the corpus spongiosum and sometimes even the corpora cavernosae.  The most distinct morphological signs of this diminished formative activity in these tissues are: a part of the urethra missing; a division in the corpus spongiosum (where it does not surround the existing portion of urethra); a ventrally incomplete prepuce; an absence of frenulum on the glans; and a chordee.  Sometimes, following an arrest of growth in the tissues forming the corpora cavernosae, under-development of the penis may occur [9] (Paparel et al., 2001).

4.2. Associated anomalies

Hypospadias appears most often in an isolated manner (Hencha-Razavi & Escudier, 2000 ; Larsen, 1996). However, it is known that other genital malformations or anomalies, some more serious than others, sometimes accompany this condition.

Alongside hypospadias, cryptorchidism [10] may also be present in the newborn male (Wese et al., 1994). Cryptorchidism may be defined as 'the uni- or bi-lateral absence of the testicles in the scrotal cavity' (Garnier & Delamare, 2000). The association of  cryptorchidism with hypospadias (observed in around 9% of cases) may be understood in relation to the endocrinal process during testicular descent (passage of the testicles through the abdomen and into the scrotum) which is similar to the embryology of hypospadias (Huston, 2002).

More rarely, the penis may be combined with the scrotum [11] ; or the position of the scrotum may change place with the root of the penis (peno-scrotal transposition) (Avolio, 2002).

Hypospadias is most severe when accompanied by these genital anomalies (Eberle, Überreiter, Radmayr et al., 1993).

5. Diversity and classification of hypospadias

There is a diversity of hypospadias. As remarked by Arap et Mitre (2000, p. 304), hypospadias may be observed in a variety of configurations, varying from an 'ambiguous aspect of the external genital organs' to 'a completely formed penis with only a superficial deficiency'.

5.1. Hypospadias or intersexuality ? 

The broader issues of  sexual ambiguity and intersexuality [12] may arise when the degree of severity of hypospadias is pronounced (e.g., with perineal hypospadias) and where other genital problems (e.g., cryptorchidism; under-developed penis) are added to the picture (Hutcheson, 2002).  In some cases it is necessary to carry out a series of examinations (e.g., palpation of the gonads, magnetic resonance imagery, caryotype) in order to determine the most probable sex of the child (Kaefer, Diamond, Hendren et al., 1999 ; Lapointe, Wei, Hricak et al., 2001 ; McAlleer & Kaplan, 2001).    

However, in the vast majority of cases, the presence of hypospadias does not lead to doubt as to the male sex of the child (46XY) or to his acceptance as a boy (American Academy of Pediatrics [AAP], 2000 ; Wilson & Reiner, 1999 ; Zemel & Slover, 2002).

5.2. Named variations of hypospadias

Various classifications of hypospadias have been proposed, defined mostly by the location of the urethral meatus at birth. For example, one such scheme is shown below (Wese et al., 1994):

Names for variations of hypospadias:        Possible locations of the urethral meatus:

1)    Glanular                                                  On the underside of the glans 

2)    Coronal                                                   At the level of the glanular-preputial ridge [13]

3)    Anterior penile                                        On the anterior third of the shaft of the penis 

4)    Median penile                                         On the middle third of the shaft of the penis

5)    Posterior penile                                      On the posterior third of the shaft of the penis 

6)    Peno-scrotal                                            At the junction of the penis and scrotum

7)    Scrotal                                                     At the level of the scrotum 

8)    Perineal                                                   At the level of the perineum 

Over time, several different classifications of hypospadias have been suggested based on the position of the urethral meatus (Sheldon & Duckett, 1987).  However, many pediatric urologists have adopted a particular classification developed, some thirty years ago, by a surgeon named Barcat (Barcat, 1973, quoted in Zaontz & Packer, 1997).  This classification, based on (possible) associated chordee, considers that hypospadias can only be classified after a surgical straightening of the penis has taken place [14]

Sheldon & Duckett (1987) contributed to the popularity of such a system, believing that there are 3 principal forms of hypospadias, within which are grouped different degrees of abnormality.  These are known as anterior (or distal); median; and posterior (or proximal) (see Figure 6). In terms of frequency, the anterior forms are the most frequent (70% of cases), followed by posterior (20%) and median (10%).



Source: Weiner and Hensle (2000).


6. Etiological hypotheses of hypospadias

Because of its frequency in the male population, there have been many investigations into the etiology of hypospadias (Baskin, 2000). It's now recognized that the etiology of hypospadias comprises hereditary, genetic, endocrinal and environmental factors (Silver, 2000)

6.1. Hereditary factors

The existence of a hereditary causal factor for hypospadias has been demonstrated by certain studies which show the presence of several affected people in the same family.  In one relatively old study (Bauer, Bull et Retik 1979; quoted in De Sy & Hoebeke, 1996), the authors concluded that if the father of a family has hypospadias, the probability that one of his sons will carry it is increased to around 8 percent, and the likelihood that one of his brothers will also be affected reaches 12 percent. Moreover, the risk for the next generation increases to around 26 percent if two members of the same family are carriers of hypospadias (e.g., when the father and one of the sons are affected). 

According to a more recent study concerning the heredity of hypospadias (Fredell, Kockum, Hansson et al., 2002), almost 7 percent of the families interviewed  - in which a child presented one or other form of hypospadias at birth -  reported knowing of the existence of another affected family member.

6.2. Genetic factors

The pathogenesis of hypospadias equally comprises factors of a genetic order.  Earlier molecular analyses have revealed that there might be, among certain boys presenting an isolated case of hypospadias, mutations of the gene responsible for the enzyme activity of 5-alpha-reductase, leading to disturbance of the production of dihydrotestosterone which is necessary for development of the male genito-urinary tract (Silver & Russel, 1999).

Recent genetic studies carried out on humans (Frisén, 2002), and on animals (Morgan, Nguyen, Scott & Stadler, 2003), have shown that alterations affecting certain genes - such as gene HOXA13 - are susceptible to change the response of the receptor to androgens (located at the level of the genital tubercule) and to lead to the phenotypic expression of hypospadias. 

6.3. Endocrinal factors

The presence of hypospadias may also be explained through certain endocrinal factors.  Nowadays, it is widely accepted that androgens play a crucial role in the development of the male external genital organs (Hugues, 2001). More precisely, recent anatomical studies support the hypothesis that androgens are essential for the formation of the ventral portion of the human urethra (Liu, Cunha, Russel et al., 2002). This type of research supports even more strongly the possibility that hypospadias can appear following deficiencies during the biosynthesis of 5-alpha-reductase or via a defect in the androgen receptors.  

It is notable also that other hormone deficiencies, such as an excessive production of the anti-Müllerian hormone (AMH) (Austin, Siow, Fallat et al., 2002), may equally play a role in the etiology of hypospadias by interfering with the biosynthesis of testosterone.

6.4. Environmental factors

In recent years a debate has begun in the scientific community about the negative impact of environmental factors on male reproduction in humans (Weber, Pierik, Dohle & Burdof, 2002).    

This debate has mostly centered on the hypothesis that certain substances of exogenous origin, known as endocrine disruptors [15], could be responsible for the appearance of disorders of sexual differentation (Toppari, 2002).  More precisely, disturbances in masculine sexual differentiation may be induced by two categories of products: the xenoestrogens and the anti-androgens (Sultan, Balaguer, Terouanne et al., 2001). Endocrine disruptors will affect in particular the normal development of the urethra, but will equally influence the physiology of testicular descent and spermatogenesis in the male (Rittler & Castilla, 2002 ; Toppari, Haavisto and Alanen, 2002).    

The list of products incriminated as endocrine disruptors is a long one.  According to Sultan et al. (2001), this list comprises diverse synthetic products such as insecticides, pesticides, fungicides, industrial chemical products, substances used in the pharmaceutical industry, detergents and materials used in the fabrication of plastics.  Certain natural substances of vegetable origin but having similar properties to hormones naturally produced in the body (animal and human), known as phyto-estrogens, have also been classified as potential endocrine disruptors (Santti, Makela, Strauss et al., 1998). It is now almost ten years since researchers alerted the scientific community to the possible links between the presence of these substances in our environment and the incidence of demasculinization phenomena [16] in diverse animal species living in the natural environment (Hose & Guillette, 1995) !

A number of experiments, some carried out on animals, have drawn attention to how substances with xenoestrogenic or anti-androgenic effects may exert their influence on the development of the male reproductive and genito-urinary system  (Gray, 1998; Gray, Wolf, Lambright et al., 1999; Hayes, Collins, Lee et al., 2002).  The injection of certain potentially anti-androgenic substances have induced hypospadias in rodents, as has finisteride (an inhibitor of 5-alpha-reductase type 2) in rabbits (Kurzrock, Jegatheesan, Cunha et al., 2000), and flutamide (an inhibitor of testosterone fixation on the special receptors) in mice (Kojima, Hayashi, Mizuno et al., 2002).  Note that these experiments using animals do not exactly mirror the situations which could be encountered by humans, but nevertheless they provide valuable information about the stages of normal genito-urinary development, as well as throwing light on the biochemical activities leading to the appearance of hypospadias.    

Scientists have recently proposed the hypothesis that endocrine disruptors may be partly responsible for hypospadias in humans (Baskin, Himes, & Colborn, 2001).  But only a limited number of studies on this subject exist.  Klip, Verloop, van Goel et al. (2002) showed that boys born to mothers who had been exposed to diethylstilbestrol [17] (DES) in utero had a higher risk of hypospadias. Another study (North & Golding, 2000), suggested that a potentially excessive consumption of phyto-estrogens (via a strictly vegetarian diet in the mother) could disrupt genito-urinary development in the male fetus.  Some studies, however, have found no accumulated risks in certain target populations. Vrijheid, Amstrong, Dolk et al. (2003) recently reported that mothers exposed (through their professional occupation) to products classed as endocrine disruptors have no increased risk of giving birth to a child with hypospadias (Vrijheid, Armstrong, Dolk et al., 2003).    

Current knowledge notwithstanding, the absence of an exact causal agent for hypospadias in humans continues to pose a problem (Baskin et al., 2001). Even today, the etiology of the majority of observed cases remains,  unexplained  (Boehmer, Nijman, Lammers et al., 2001 ; Sharpe, 2003).   

7. Epidemiology

7.1. Frequency

In the specialist field of pediatric urology, it is reported that hypospadias is a common congenital malformation.  The estimations of frequency are placed between in 300 (0.3 %) and in 250 (0.4%) of male births (Baskin, 2000 ; Sheldon & Duckett, 1987 ; Paparel et al., 2001).

7.2. Incidence

However, certain scientific studies published towards the end of the 1990s reported an increasing incidence of hypospadias in several western countries. Based upon the analysis of American and European surveys of congenital malformations and earlier epidemiological reports, Paulozzi, Erickson et Jackson (1997) observed that the rate of hypospadias almost doubled [18] between 1970 and 1990 in the United States. Paulozzi (1999) also stated that similar increases in hypospadias had been reported in several European countries [19].   

A series of recent publications, based upon hospital birth registers, have reported an increase in hypospadias. One study carried out by Pierik, Burdof, Nijman et al. (2002) produced evidence that the frequency of hypospadias rose to 0.7 percent in child health centers situated in the south west region of the Netherlands; this represented a rate 6 times higher than that generally reported in the region by national registers.  Another study by Hussain, Chagtai, Herndon et al. (2001) showed an incidence 10 times higher (4.0% vs 0.4 %) of hypospadias in 2000 compared to 13 years previously (1987) in neo-natal intensive care units in the USA (Connecticut) [20]..  

Other studies using different registers have discovered a higher frequency of hypospadias than is generally recognized. After an analysis of American national military registers, Gallentine, Morey and Tompson (2001)  estimated a frequency of hypospadias rising to  0.7% (709 cases of hypospadias counted in 99210 males). By contrast, this frequency (0.7%) is almost double that calculated by other researchers in Italy, in a male population over 18 years of age who were examined during enrolment for military service, which reached 0.36% (42 cases per 11649 males) (Mondaini, Ponchietti, Bonafè et al., 2001).   

What explanations does the scientific community give regarding these rises?  The concept of endocrinal disruption, as discussed above, has been increasingly accepted and proposed as a way of accounting for the increased incidence of hypospadias observed in more industrialized nations (Dolk, 1998 ; Harrison, Holmes & Humfrey, 1997 ; Wakefield, 2001). However, a number of authors agree that new epidemiological research of a multi-disciplinary nature must be carried out, in order to clarify the part played by chemical substances disrupting endocrine function in the reported increased frequency of hypospadias (Baskin et al., 2001; Rittler & Castilla, 2002; Sultan et al., 2001; Toppari et al. 2002; Weber et al., 2002).    

Taken together, the published studies draw attention to the fact that nowadays hypospadias is a congenital condition far more common than is normally supposed (Sharpe, 2003).

8. Conclusion

Hypospadias benefits from a vast literature concerning the investigation of its physical aspects.  Currently, different medical disciplines are working together to understand better the etiology of this condition. The data currently available on this subject stem from endocrinology, molecular biology, epidemiology and even eco-toxology.  Although some considerable progress has  been made in these fields, supplementary research is required to better understand the factors combining to produce this condition.

This review of the relevant literature shows that hypospadias is a much more common condition than is generally supposed, that it is becoming increasingly common, and indeed that it is more common now than ever before.

[1] The mechanisms of prenatal sexual differentiation have been to a large part elucidated by the many experiments carried out, some 50 years ago, on different animal species (batrachians, mammals and birds) (for a review see Aron, 1973, pp. 109-121).

[2] The gonadic outline is called undifferentiated when it contains both ovarian and testicular tissue.

[3] SRY : Sex determining Region Y gene. Only a tiny region (known as the 'short arm' of the Y chromosome contains the gene(s) of sexual determination (see Haqq & Donahoe, 1998, pp. 2-5).

[4] In the absence of SRY, the undifferentiated gonad develops as an ovary.

[5] In the absence of AMH (anti-Müllerian hormone) and testosterone, sexual differentiation follows a fixed pattern, characterized by the regression of the Wolfian ducts and the development of Müllerian ducts (the upper third of the vagina and uterus).

[6] This severity of hypospadias is also classified as vulviform; the external genital organs of the newborn male (46XY) can appear as the phenotypic feminine. 

[7] The prepuce is known as a dorsal hooded foreskin.

[8] In fact, certain varieties of hypospadias with a complete prepuce have been reported in the literature (see, for example, Cold & Taylor, 1999).

[9] A penis of under-developed size, sometimes observable in hypospadias, is not to be confused with what has been called a micropenis or microphallus: here the penis is morphologically normal and the urethra's outlet is well positioned at the end of the glans, but the size is very much reduced in comparison to the available norms (Bourgeois, 2003).

[10] The non-descent of testicles (without the association of hypospadias) is a condition frequently encountered in newborns of the masculine sex, its incidence being estimated at around 3 percent of full-term newborns (Leissner, Filipas, Wolf & Fish, 1999).

[11] Impacting of the penis in the scrotum is defined by the presence of scrotal skin, either low or high on the body of the penis.  Total impacting is rare, but if this is the case only the dorsal face is visible, the ventral side remains stuck in the scrotum. 

[12] The notion of sexual ambiguity relates to an undifferentiated or badly differentiated appearance of the external genital organs, or to a state of discordance between the internal and external genital organs (Encha-Razavi & Escudier, 2000). The notion of intersexuality refers to a variation of normal development whereby the appearance of the external genitals makes it difficult to assign a sex to the child at birth (Hugues, 2002).

[13] The balano-preputial ridge is the anatomical transition between the glans and the shaft of the penis.

[14] The explanation of such a classification is relatively easy to explain: the position of the urethral meatus is considered an untrustworthy criterion for judging the severity of hypospadias as, in general, the meatus moves backwards after surgical repair of the chordee (orthoplasty), worsening to some extent the degree of hypospadias confirmed initially (De Sy & Hoebeke, 1996).

[15] The concept of endocrinal disturbance refers to the molecules capable of imitating sexual hormones naturally produced by the body (xenoestrogens) or of blocking certain hormones (anti-androgens) at the stage crucial for sexual development in utero (Toppari, 2002).  

[16] I cite as an example the research of Facemire, Gross and Guillette (1995) and that of Guillette (2000) (in Florida, USA). In a first study, the researchers clearly gave evidence that the abnormally high presence of cryptorchidism, observed in a population of panthers, could be explained by the fact that these felines lived very close to an agricultural area where pesticides were widely distributed. (Facemire et al., 1995). In a second series of studies, the researchers noticed a notable diminishing of the penis size of alligators born in a polluted lake (Lake Apopka) following a leakage of toxic substances (Guillette, 2000; see also Semenza, Tolbert, Rubin et al., 1997).

[17] Diethylstilbestrol (DES) is a synthetic estrogen which was widely prescribed to pregnant women between 1938 and 1975 to prevent miscarriage. The effects of DES as evidenced are avowed to be transgenerational. In the article by Klip et al. (2002), the hypothesis is that DES would be associated with a disturbed function of the placenta, resulting in a diminishing of placental and fetal hormones which could disrupt fetal development; this would predispose a likelihood of hypospadias.

[18] The rate has gone from 20/10000 in 1970 to 40/10000 in 1993 in USA (Paulozzi et al., 1997).

[19] Norway, Sweden, United Kingdom, Denmark, Italy and France (for details see Paulozzi, 1999).

[20] Other American researchers have reported an incidence, also in neonatal intensive care units (in the Atlanta region), ten times higher than normally estimated in that particular population (11% vs 1%) (Gatti, Kirsch, Troyer et al., 2002).