Genetic Basis of Homosexuality

The genetic basis of homosexuality can be explicated in research papers from the writers at Paper Masters. Our writers will examine studies on the genetic basis of homosexuality and review and report on them for you in a research project.

Evidence for genetics as a basis for sexual attraction came from studies of fruit flies. Researchers were able to show that sexual dimorphism existed in genetically altered fruit flies. Of course, the behavior of fruit flies cannot be equated to behavior in humans, but it suggested a line of investigation. Later studies were done on human twins. The two types of twins used are as follows:

• Identical twins are called monozygotic twins and their genomes are identical.
• Fraternal twins are called dizygotic twins and they share as much genetic material as other siblings.

Richard Pillard of Boston University and Michael Bailey of Northwestern University performed a study with 56 monozygotic twins, fifty-four dizygotic twins, and fifty-seven adoptive brothers who were unrelated. The use of twins is important because they genetically related twins share genetic material while the adoptive brothers do not.

Genetic Component to Sexual Attraction

If there is a genetic component to sexual attraction, then the more genetic material that two people share, the more likely they are to exhibit the same sexual preference. Pillard and Bailey's study showed a concordance rate of 52 percent for monozygotic twins, 22 percent for dizygotic twins, and 11 percent for the adoptive brothers. Concordance is the sharing of a trait by each twin. The results of the study indicate a genetic component to homosexual attraction. Genetics could be as much as 70% of the cause of sexual preference. Pillard and Bailey believe that other factors are both biological and environmental and that they manifest themselves early in life. Their study could not determine how many genes were involved in sexual preference. Critics of the study complain that the manner in which Pillard and Bailey recruited subjects did not result in a random sample. They sought subjects through notices in gay publications. Critics argue that the motivation of these subjects is open to question. Furthermore, critics contend that studies of twins do not always account for environmental factors.