Homosexual behavior is always under great scrutiny by religious sects. However, there are strong genetic explanations for this behavior. Homosexuality has been noted in all studied species, with the exception of ostrich. Freud believed that every person is inherently bisexual, at birth. However, at about 4 years of age he believes this changes.

Beginning in the 1950s, animal research began to show a very powerful effect of hormones on the development and differentiation of the brain. It was found, for example, that the sexual behavior of rats and mice could be altered by exposure to the male hormone testosterone during a critical window of time during development. Of perhaps more relevance to humans is the fact that female monkeys exposed to testosterone during prenatal development tend to play with other monkeys in a manner more typical of male monkeys. This observation is especially intriguing because some scientists...