What causes atypical genitalia (ambiguous genitalia)?

What causes atypical genitalia (ambiguous genitalia)?

Hormonal irregularities during pregnancy generally cause atypical genitalia. These irregularities interfere with your fetus’s developing sex organs. Causes vary depending on the number or combination of sex chromosomes that are present.

46 XX DSD

With 46 XX DSD, your baby’s internal sex organs include ovaries and a uterus, but their external sex organs may resemble a penis and testicles. 46 XX occurs when your baby is exposed to too many male hormones (androgens) when their external genitals are forming. The most common cause of 46 XX DSD is a disorder called congenital adrenal hyperplasia (CAH). In this condition, your baby’s adrenal glands produce excessive amounts of androgens.

46 XY DSD

With 46 XY DSD, your baby’s internal sex organs are male but external sex organs are unclear. 46 XY occurs when your baby’s testes don’t develop properly, they don’t make enough testosterone or your baby’s body can’t use the testosterone correctly.

Disorders of gonadal differentiation

With disorders of gonadal differentiation, your baby’s sex organs don’t develop completely into testes or ovaries. Mixed gonadal dysgenesis means the sex organs (testes or ovaries) may not fully develop. Partial gonadal dysgenesis means your baby’s sex organs form only some testicular tissue and the testes won’t work properly. Gonadal dysgenesis means both gonads stay premature and they won’t develop into testes or ovaries.

Ovotesticular DSD

With ovotesticular DSD, your baby’s sex organs have ovarian and testicular tissue, or your baby has one ovary and one teste. This is very rare.