Birth defects of the genitals in boys can involve the penis, scrotum, or testes (testicles).
Genital birth defects may be caused by abnormal levels of sex hormones during fetal development, chromosome abnormalities, environmental factors, or inherited factors.
The diagnosis depends on the defect and may include imaging tests.
Many genital defects require surgery.
(See also Overview of Kidney and Urinary Tract Birth Defects.)
Causes of Male Genital Birth Defects
Male and female sex organs develop from similar tissue in the embryo. Whether this tissue develops into male or female sex organs depends on a number of factors. One factor is the sex chromosomes, which are called X and Y. Normal males have 1 X and 1 Y chromosome. Normal females have 2 X chromosomes. Early in development, a fetus with a Y chromosome begins developing testes, which secrete the male hormone testosterone. Testosterone activates pathways that cause development of the scrotum, penis, and penile urethra (the urine passage through the penis). Without testosterone (as in a normal female fetus), the genitals become the clitoris, labia majora, and separate vaginal and urethral canals. In addition to testosterone, there are other substances made by the developing fetus that help control genital development.
There are several factors that cause male genital birth defects, but the most common problem is abnormal levels of sex hormones in the fetus before birth, particularly having too little testosterone.
Other factors that can interfere with normal development of the genitals include
Abnormal or missing genes (the DNA code of instructions for how the body works)
Exposure of the fetus to substances, such as certain medications, drugs, and hormones, that interfere with genital development
Sometimes, the factor that causes a genital defect also causes a defect in another organ.
Children who have genital defects may have problems urinating. Later in life, they may have difficulties engaging in sexual intercourse, impaired fertility, social and psychological problems, or a combination.
Types of Male Genital Birth Defects
There are several causes of male genital defects, but most involve abnormal levels of sex hormones in the fetus before birth.
Defects of the penis may interfere with a boy's ability to direct the stream of urine while standing. For older males, the defects may interfere with the ability to have sexual intercourse and with sperm delivery, which may impair fertility. These defects can also cause problems with self-esteem because of their appearance.
Common genital birth defects in boys include
Urethral opening in the wrong place (hypospadias and epispadias)
Unusually small penis (microphallus)
Abnormal curvature of the penis (chordee)
A foreskin that is too tight (phimosis) or becomes trapped behind the head of the penis (paraphimosis)
Male Reproductive Organs
Hypospadias
In hypospadias, the opening of the urethra (the tube that drains urine from the bladder out of the body) is on the underside of the penis:
Mild hypospadias: The opening is located just below the normal position on the tip of the penis.
Moderate hypospadias: The opening is located somewhere on the shaft of the penis.
Severe hypospadias: The opening may be located in the scrotum or between the scrotum and the anus.
Because urine may spray downward, boys who have severe hypospadias may need to sit down to urinate. Boys who have hypospadias often have another defect called chordee (a downward bend of the penis) and an incompletely developed foreskin, in which the foreskin is located on the top of the penis and does not encircle the underside (called a hooded foreskin because it looks like a hood on the penis). The more severe the hypospadias, the more severe the chordee and foreskin abnormalities.
Before removing the foreskin (circumcising) in a newborn with hypospadias, parents should consult a urologist (a doctor who specialize in the diagnosis and treatment of disorders of the urinary tract and male reproductive system). Sometimes doctors need the foreskin tissue when they do surgery to correct hypospadias.
Mild hypospadias may not need treatment. Other children usually have surgery to correct the defect at about 6 months of age. Often the surgery can be done on an outpatient basis (the child does not have to stay in the hospital overnight).
In this image, the arrow is pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Image courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
In this image, the arrow is pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Image courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
In these images, the arrows are pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Images courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
In this image, the arrow is pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Image courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
In this image, the arrow is pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Image courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
In these images, the arrows are pointing to the outside opening of the urethra (the tube that drains urine from the bladder out of the body).
Images courtesy of Drs. Ronald Rabinowitz and Jimena Cubillos.
Epispadias
In epispadias, the opening of the urethra is located on the top side of the penis instead of at the tip. Children who have epispadias may leak urine (urinary incontinence). Boys who have the most severe form of epispadias often also have another disorder called bladder exstrophy. In bladder exstrophy, the bladder does not completely close and opens out onto the surface of the abdomen, allowing urine to drip through the open bladder rather than the urethra.
Surgery is done to correct epispadias.
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Unusually small penis (micropenis)
Some boys have an unusually small penis. This defect is called micropenis or microphallus. Sometimes micropenis occurs in boys who do not have enough of the male hormone testosterone.
Chordee
Chordee is a curvature of the penis. The penis may bend downward, upward, or sideways or may be twisted. The bend may affect a boy's ability to direct the stream of urine while urinating.
If the bend is not severe, it may not need to be surgically corrected. If the bend is severe, surgery may be needed. People may choose to correct chordee if they are concerned it will affect their ability to have sexual intercourse or for cosmetic reasons.
Other defects of the penis
Some boys are born with a very tight frenulum (tissue located under the foreskin that helps pull the foreskin over the glans). A tight frenulum may prevent the foreskin from being completely pulled back over the tip of the penis. It may also cause pain or bleeding when the foreskin is pulled back or during an erection.
To treat the symptoms, doctors may surgically remove or cut the frenulum when the boy is older.
Diagnosis of Male Genital Birth Defects
Physical examination
Rarely imaging tests, such as ultrasound and magnetic resonance imaging
Doctors do a physical examination of the child's genitals and look for other birth defects. If doctors do not feel one of the testes during the examination, they may do laparoscopy, in which they look inside the abdominal cavity using an endoscope.
Rarely, doctors do ultrasound or sometimes magnetic resonance imaging (MRI) to identify the presence of the testes.
Treatment of Male Genital Birth Defects
Surgery
Most children who have genital defects need surgery to correct the defects. Some minor defects do not need surgery.
