Sex is not always clear-cut. Occasionally, a hormone imbalance before birth produces a hermaphrodlte person In whom sexual tfferentlattou Is ambiguous0 or Incomplete. Hermaphrodites tend to have some combination of male and female genitalia. In one case, for example, a chromosomally normal (XY) male was born with a penis just one centimeter long and a urinary opening similar o that of a female. Some people may be genetically of one sex but have a gender ide. ity of the other. That is true for a ralls lal, a person ill whom the sex-related structures of the brain that define gender identity are opposite from the physical organs of the person’s body. Consequently,transsexuals often feel that they are the oppositesex from that of their sex organs. ranssexuals maybecome aware of this conflict between gender identity and physical sex as early as the preschool years. Some transsexua.s take hormone treatments or have a sexchange operation to alter their genitalia in order to achieve a body congruent with their sense of sexual identity. Many transsexuals who receive hormone treatments or undergo surgical procedures go on to lead lives that the)’ view as being compatible with their true sexual identity. Western societies acknowledge the existence of only two sexes; some other societies recognize three-men, women, and berdaches (or hijras or xaniths), biological males who behave. dress, work, and are treated in most respects as women. TIle closest approximation of a third sex in Western societies is a transvestite, a male who lives as a woman or a female who lives as a man but does not alter the genitalia. Although transcripts are not treated as II third sex, they often “pass” for members of that sex because their appearance and mannerisms fall within the range of what is expected from members of the other sex.Transsexuality may occur in conjunction with homosexuality. but this is frequently not the case. Some researchers believe that both transsexuality and homosexualityhave a common prenatal cause such as a critically timed hormonal release due to stress in the mother or the presence of certain hormone-mimicking chemicals chemicals chemicals during critical steps of fetal development.Researchers continue to examine this issue and debate the origins of transsexuality and homosexuality.