Which deficiency is characterized by a female presenting with ambiguous genitalia?

The presence of ambiguous genitalia in a female can be attributed to a deficiency in 17-hydroxylase. This enzyme is crucial in the adrenal steroidogenesis pathway, particularly in the production of sex steroids. In 17-hydroxylase deficiency, there is an impaired conversion of progesterone and pregnenolone to cortisol and sex hormones, which leads to an overproduction of mineralocorticoids. The lack of adequate estrogen and other sex hormones results in underdeveloped or ambiguous external genitalia in genetically female individuals (46,XX), despite normal ovaries being present.

In contrast, conditions caused by deficiencies in 21-hydroxylase and 11-hydroxylase typically lead to virilization due to the accumulation of adrenal androgens, which can cause masculinization rather than ambiguous genitalia. Furthermore, 5-alpha reductase deficiency affects male genital development. In this condition, genetically male individuals (46,XY) have impaired conversion of testosterone to dihydrotestosterone (DHT), resulting in ambiguous or female-like external genitalia, but it specifically pertains to males and does not apply in this context regarding females.

Thus, the correct answer points toward 17-hydroxylase deficiency