Chapter 1. Homosexuality and the Nature-Nurture Debate

Short Description

The clip visits the bedrooms of two young boys, Jared and Adam. The rooms are a study in contrast.

Long Description

One reflects strongly masculine interests, the other very feminine. Jared is eager to show the narrator his GI Joe collection. Adam displays his baby doll. He also wears bright red nail polish. Adam’s behavior is labeled “childhood gender nonconformity.” Children who show this pattern of behavior tend to grow up gay.

The boys’ mother, Danielle, reports that the difference in her sons’ behaviors became apparent at 18 months.

Psychologist, Michael Bailey, suggests that cases such as Jared and Adam indicate that nature, rather than nurture, shapes sexual orientation. Although the research indicates that homosexuality runs in families, it has also been found that identical twin pairs can have different sexual orientations. For example, twins Steve and Greg had the same upbringing but one is gay and the other is not. Although they showed different interests in childhood, it was not until they were in high school that their different sexual orientation was evident.

This difference in identical twins, admits Bailey, indicates that sexual orientation is not entirely genetic. Environmental influences, he continues, include those that occur already in the womb. In fact, research suggests that prenatal influence can be very important.

At Michigan State University, Marc Breedlove has found that the hormones a rat is exposed to at birth can change its sexual orientation. Rats are born underdeveloped, so this exposure comes at a stage when humans are still in the womb. A female rat injected with testosterone at birth shows a sexual behavior pattern characteristic of a male. A male, castrated at birth (and thus deprived of testosterone), shows a sexual pattern characteristic of a female.

Other research on sexual orientation has revealed the “older brother” effect. The more older brothers a man has, the greater the probability that he will be gay. There is no corresponding effect for lesbians. One explanation for this effect is that the mother produces antibodies when she conceives her first boy, and these antibodies affect the sons she subsequently carries. Strangely, this effect holds for right-handed but not for left-handed men.

Trying to apply these theories to the real cases presented in the clip merely highlights the complexity and continuing riddle of sexual orientation. At this point, there are many more questions than answers.

Questions