Birth defects of the genitals can involve the penis, scrotum, or testes (testicles) in boys and the vagina and labia in girls. Sometimes the genitals are ambiguous, that is, not clearly female or male.
Genital defects may be caused by abnormal levels of sex hormones during fetal development, chromosome abnormalities, environmental factors, or inherited factors.
Sometimes the genitals are not clearly male or female (ambiguous genitals), which is most common in girls with congenital adrenal hyperplasia.
To determine the sex of an infant who has ambiguous genitals, a physical examination, imaging tests, and blood tests to analyze chromosomes and measure hormone levels are done.
Many genital defects require surgery.
Parents have many factors to consider before assigning a gender to a baby born with ambiguous genitals.
(See also Overview of Kidney and Urinary Tract Birth Defects.)
Causes of 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 things. One factor is the sex chromosomes, which are called X and Y. Normal males have one X and one Y chromosome. Normal females have two 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.
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 drugs and hormones, that interfere with genital development
In many of these factors, the common problem is abnormal levels of sex hormones in the fetus before birth, particularly having too much testosterone (or testosterone-like substances) in girls and too little testosterone in boys.
Sometimes, the disorder that causes genital defects also results in defects of other organs.
Symptoms of Genital Birth Defects
Sometimes genitals appear abnormal but are still apparently male or female. Such defects in boys include abnormalities of the urethral opening (for example, being located on the bottom or, less often, the top of the penis), an abnormally shaped penis (chordee), and an undescended testis. Defects in girls include a hymen that has no opening (imperforate hymen) and a missing or shortened vagina.
Other defects result in genitals that are not clearly male or female. These are called ambiguous genitals. The most common cause of ambiguous genitals is in girls who have congenital adrenal hyperplasia. Congenital adrenal hyperplasia is an inherited problem with the adrenal glands that causes the glands to produce too much testosterone (the adrenal glands naturally produce a small amount of testosterone in healthy girls).
Children who have genital defects may have problems urinating. Later, people may have difficulties engaging in sexual intercourse, impaired fertility, social and psychologic problems, or a combination.
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Diagnosis of Genital Birth Defects
Physical examination
Sometimes imaging tests, such as ultrasonography and magnetic resonance imaging
Sometimes blood tests to analyze the chromosomes and hormone levels
Doctors do a physical examination of the child's genitals and look for other birth defects.
Often, doctors do ultrasonography or sometimes magnetic resonance imaging (MRI) to identify the presence of testes, ovaries, and a vagina. They may do a retrograde genitogram to outline the urethra, or they may also use a thin viewing tube (cystoscope) to look in the opening of the urethra and/or vagina to detect abnormalities. If the results of these tests are unclear, doctors may do laparoscopy, in which they look inside the abdominal cavity using an endoscope.
Doctors usually do blood tests to see what sex chromosomes the infant has and to measure hormone levels.
Treatment of Genital Birth Defects
For genital defects, surgery
For ambiguous genitals, sometimes gender assignment surgery and hormones
Most children who have genital defects need surgery to correct the defects. Some minor defects do not need surgery.
Regarding children with ambiguous genitals, children's sex chromosomes (that is, whether they are a genetic female with XX chromosomes or a genetic male with XY chromosomes) are an important factor, but other things also must be considered. For example, the hormones the fetus was exposed to in the uterus can have a significant effect. However, this effect may not be apparent until children are old enough to begin acting like one gender or another or to think of themselves as one gender or another (gender identity).
Because children's behavior and gender identity do not always match their genetic gender, it is important not to make the gender assignment too soon. Waiting is not harmful because it is not essential to assign a gender during infancy. A multidisciplinary care team that includes the pediatrician, endocrinologists (specialists in hormone disorders), geneticists, urologists, and possibly psychiatrists can advise parents facing this challenging decision.
When appropriate and indicated, surgery is done and children are given hormones. Children may need to take hormones for the rest of their life.
Female Genital Defects
There are several causes of female genital defects, but most involve abnormal levels of sex hormones in the fetus before birth.
Some genital birth defects in girls include
Ambiguous genitals (genitals that are not clearly male or female), which is often caused by congenital adrenal hyperplasia
Rarely, the vagina may be missing or shortened.
To diagnose genital birth defects, doctors do a physical examination and tests.
External Female Genital Organs
Male Genital 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)
Some boys are born with genitals that are not clearly male or female (called ambiguous genitals). A common cause of ambiguous genitals in boys is testosterone deficiency during early pregnancy (see also Male Hypogonadism in Children).
To diagnose genital birth defects, doctors do a physical examination and tests.
Male Reproductive Organs
