Intersex is a group of conditions where there is a discrepancy between the external genitals and the internal genitals the testes and ovaries. The older term for this condition is hermaphroditism. Although the older terms are still included in this article for reference, they have been replaced by most experts, patients and families. Increasingly, this group of conditions is being called disorders of sex development DSDs. Note: In many children, the cause of intersex may remain undetermined, even with modern diagnostic techniques.

Documented sex differences in brain structure are typically taken to support this dimorphic view of the brain. However, neuroanatomical data reveal that sex interacts with other factors in utero and throughout life to determine the structure of the brain, and that because these interactions are complex, the result is a multi-morphic, rather than a dimorphic, brain. The last two decades have seen a resurgence of interest in the ancient question of whether men and women are fundamentally different.

The Intersex Society of North America closed its doors and stopped updating this website in For current information, links to intersex support groups, and to connect with intersex advocates, please head to interACT: Advocates for Intersex Youth. For example, a person might be born appearing to be female on the outside, but having mostly male-typical anatomy on the inside.