Ambiguous genitalia

DEFINITION: Abnormal primary sexual characteristics caused by genetic defects

• ALSO KNOWN AS: Disorders of sex development, intersex
• ANATOMY OR SYSTEM AFFECTED: Genitals, reproductive system, urinary system
• CAUSES: Chromosomal defect, inappropriately elevated or diminished hormone levels in utero
• SYMPTOMS: Abnormal appearance of primary sexual characteristics, infertility, urinary tract problems
• DURATION: Chronic
• TREATMENTS: Hormone therapy, psychological counseling, surgery

Causes and Symptoms

Ambiguous genitalia is usually caused by a variation in the number of sex chromosomes or in prenatal exposure to key hormones. Males normally possess one X and one Y chromosome, while females normally have two X chromosomes. When an embryo has a different number or configuration of these chromosomes, normal urogenital development is disrupted and, in some cases, the resulting internal and external sex organs do not match. Inappropriate levels of male and female hormones during fetal development are also responsible for ambiguous genitalia. The main categories of ambiguous genitalia conditions are true gonadal intersex (formerly called hermaphroditism), 46, XY intersex (“male pseudohermaphroditism”), and 46, XX intersex (“female pseudohermaphroditism”). Patients, their families, and experts often use the term “disorders of sex development” (DSDs) to refer to intersex conditions.

True gonadal intersex is a condition in which testicular and ovarian tissues are found in the same person, and their urogenital development is ambiguous. A baby with an enlarged clitoris resembling a penis (clithoromegaly) and fused labial-scrotal folds may be assigned to the male sex at birth, whereas a baby with a normal clitoris and open labial-scrotal folds might be assigned to the female sex at birth. Hypospadias, a condition in which the urethra opens somewhere around or along the clitoris, penis, or vaginal canal, often occurs and lends further ambiguity to the appearance of the external genitalia. Similarly, testicles may be or believed to be undescended. The exact cause of this condition is generally unknown.

Persons with 46, XY intersex may develop internal testes, but their external genitals at birth appear female, incompletely male, or indeterminate. The undervirilization responsible for 46, XY intersex results from a lack of testosterone during fetal development. Among the causes are testicular malfunction; inadequate testosterone production; 5-alpha-reductase enzyme deficiency (sometimes called “guevedoces syndrome”), in which testosterone cannot be converted to 5-alpha-dihydrotestosterone (DHT), the inducer needed for the early development of male tissues; or malfunction in testosterone receptors, known as androgen insensitivity syndrome (AIS) or testicular feminization syndrome (TFS).

Individuals with AIS may lack ovaries, fallopian tubes, and a uterus, but have a “blind” (dead-end) vagina and breasts; testes may or may not be present. As they enter puberty, they begin to grow genital hair and breasts and have a feminine appearance because they are unable to respond to testosterone. Menstruation will not occur, however. When individuals with 5-alpha-reductase enzyme deficiency begin puberty, the clitoris enlarges into a penis-like structure without a urethra. The urethral opening is at the base of the enlarged clitoris. One or both of the internal testes descend into scrotal sacs, and the teenager begins to develop masculine body and facial hair, but there is no breast development. In some cases, the voice deepens, and muscle mass and body shape become more masculine. At puberty, the testes produce very large amounts of testosterone, which is able to make up for the lack of DHT and to stimulate some tissues to develop further.

Persons with 46, XX intersex often have clithoromegaly and fused labia, while the female internal organs develop normally. Female hormones produced at puberty lead to the development of female secondary sex characteristics, unless testosterone is administered. The virilization that causes 46, XX intersex may result from congenital adrenal hyperplasia, a kidney disorder that produces excess androgen in the fetus; ovarian tumors in the mother; aromatase enzyme deficiency, in which male hormones cannot be converted to female hormones; or other sources of prenatal testosterone exposure.

Treatment and Therapy

The most common forms of treatment are hormone therapy and surgery. If a person with ambiguous genitalia develops gender dysphoria, a conflict between their physical gender and the gender they identify with, they may decide to pursue sex reassignment through hormone therapy or surgery. Surgery may be required at birth to correct hypospadias or other conditions that impair proper urinary function. Concerned parents should consult with their physicians about the child’s specific condition, the possible underlying causes, and the risks and benefits of various treatment options. Psychological counseling is recommended for parents and individuals with ambiguous genitalia, particularly with respect to making treatment decisions.

Perspective and Prospects

In the past, parents and physicians were quick to assign a sex to an infant with ambiguous genitalia and pursue surgery to make the genitalia more recognizably male or female. Immediate surgery is now recommended only to improve or restore function, and families are encouraged to involve the intersex person in making decisions about their gender identity and treatments that support those decisions.

In general, persons with ambiguous genitalia are content with their assigned sex and are no more likely to seek sex reassignment or to change gender later in life than are persons born with normal genitalia. However, gender-atypical behavior may be associated with some DSDs. Individuals with disorders of sex development also appear just as likely to be heterosexual as the general population. Normal puberty may be absent in affected individuals, and fertility can be an issue in adulthood.

Bibliography

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