Ambiguous genitalia is a form of intersex affecting 0.05% of the population, causing them to have genitals that may have characteristics of male and female sexes or may be incompletely developed. The external sex organs may not match the internal sex organs or their chromosomes. Ambiguous genitalia may appear as a large clitoris or as a small penis and/or a fused labia or empty scrotum. People with ambiguous genitalia can have any have internal sex organs or combination of sex organs, they can have any chromosomes, and their bodies may produce either hormones during puberty.
Male and female sex organs develop from the same tissue. Whether this tissue becomes male organs or female organs depends on the chromosomes and the presence or absence of male hormones in the womb. Atypical hormone levels or chromosomal abnormalities can cause ambiguous genitalia. Infants with ambiguous genitalia are often given nonconsensual surgery to "correct" their genitalia and make them appear more male or female.
People with ambiguous genitalia are also sometimes known as hermaphrodites, though the term is considered offensive as it tends to generalize them and act as if them having ambiguous genitalia is the only interesting thing about them. It also stigmatizes the topic and encourages fetishists.