"Born Eunuchs" Home Page and Library:
http://www.well.com/user/aquarius/Almost all people are bisexual by nature, although most people choose, or are conditioned, to limit themselves to the opposite sex. Thus, for almost all so-called "straight" people, their sexual identity is defined by their behavior, and is subject to influence or change. In fact, in the ancient world, most people were actively bisexual in their behavior at different times in their lives.
However, as a minority, gays differ by nature from the majority -- not in our attraction to the same sex, but only in our physical lack of response to the opposite sex. Being naturally impotent for procreative sex, innately gay men were referred to in the ancient world as "born eunuchs" or just "eunuchs." Meanwhile, women who innately lacked response to men were seen as a particular kind of "virgins."