Intersex
The intersex flag.

Intersex means a variation in sex organs, hormones, and chromosomes, making the individual neither male nor female. Intersex characteristics may not be as obvious as a difference in genitals, however. Many intersex people do not know of this part of them until much later in life, sometimes not even until after death, due occurrences where the only differences are much less noticeable. There's no definite definition to intersex given its nature of being a series of variations, but there are certain guidelines.