Slide 2 Notes
There are three basic types of sexual orientation in the human population, which are heterosexual, homosexual, and bisexual. Heterosexual is the term reserved for those who are attracted to the opposite sex, and homosexual refers to those who are attracted to their own sex. Bisexual is, of course, those who are sexually attracted to both sexes. There are many perspectives from which to view sexual orientation. In this presentation three will be discuss: genes, sex hormones, and sexual identity.
Slide 3 Notes
It has become apparent as of late that homosexuality has a basis in genetics as well as through social-learning (Pinel, 2007). There is strong evidence taken from studies of monozygotic twins which corroborates the belief that homosexuality is genetic. In one study 52% of monozygotic twin brothers were found to be homosexual if one was homosexual. It was also established that 48% of female monozygotic twins were homosexual if one was homosexual in this study. This evidence draws a strong correlation between genetics, through the identical twins, and human behavior; namely, homosexuality.
Slide 4 Notes
Sex hormones play a big role in prenatal gender differentiation. In fact, without androgens we are all destined for femininity. However, do sex hormones play a part in sexual orientation? It might be assumed that a homosexual person has lower levels of sex hormones, which might account for their same-sex preferences. This has been shown to be false. In fact, the hormones of a homosexual person are the same as a heterosexual person. On the other hand, perinatal androgen injections have been shown to change sexual preferences in animal experiments. Also a strong correlation has been drawn between estrogen and its effects on prenatal females. There is a weak indication that estrogen affects homosexual tendencies in females, but does not have the ability to directly change sexual preferences.
Slide 5 Notes
Lastly, it is important to keep in mind that sexual preferences, gender identity, and physiological sex are three independent entities. Take transsexuals for instance; they are one physiological sex and yet have a different gender identity. Also transsexuals might be attracted to either sex independent of physiology or gender identity. This fact is strong evidence that “maleness” and “femaleness” are not mutually exclusive; that gender and sex are loosely defined within the complex framework of sexual preference.
Slide 6 Notes
In conclusion, sexual orientation is determined by many factors including genes, perinatal and prenatal sex hormones, and our own sexual identity. It is clear that gender identity, physiological sex, and sexual preferences interact in a very complex manner to create individual people with individual identities.
Pinel, J. P. J. (2007). Basics of biopsychology. Boston, MA: Allyn and Bacon.