Homosexuality

1
Homosexuality

• Learned or innate?

Kimberly Metzger Monica Wolking
2
Are some born gay?

• With more research being conducted, science is
  turning to the view that sexuality is innate
• It has never been proven that parental sexual
  behavior affects their childs sexual orientation
• Homosexuals act differently than do heterosexuals
  at an early age
• Research has indicated male sexual orientation is
  genetic

3
Lines of Evidence

• Two lines of evidence suggest sexual orientation
  is innate
• 1. Neuroendocrine Studies
• 2. Genetic Studies

4

Genetic Studies

• Much research has been done on the twins of gay
  men. When studied by Bailey and Pillard
• 52 of their identical twin brothers were gay
• 22 of their non-identical twin brothers were gay
• 11 of their adoptive brothers were found to be
  gay

5
Neuroendocrine Hypothesis

• Early effects of androgens on neural structures
  determine sexual orientation
• If high levels of androgens--result is that
  structures are masculinized, and an attraction to
  women
• If low levels of androgens--result is an
  attraction to men

Consistent with this, gay men and lesbian women
recall substantially more gender atypical
behavior in childhood than do heterosexuals.
6
Hypothalamic Structures

• The anterior hypothalamus is partially
  responsible for male-typical behavior
• Studies have shown that the hypothalamus is
• Two times larger in heterosexual men than in
  women
• Also twice as large in heterosexual men than in
  homosexual men
• This points to sexual orientation as biological

7
LeVays Studies

• Studied the brains of gay men who had died of
  AIDS, as well as heterosexual men and women who
  had died of other causes
• Looked at nuclei in the hypothalamus
• Found a difference in the size of the nuclei
  INAH-3 for men and women
• The size of INAH-3 is not the sole cause of
  sexual orientation
• Many critics of LeVay

8
Allen Gorski Studies

• Looked at the anterior commissure of the corpus
  callosum
• Found it to be relatively larger in heterosexual
  women and homosexual men than those in
  heterosexual men

9
National Institute of Health Study

• Found that one form of male homosexuality is
  carried on the X chromosome and is passed from
  mothers to their sons

10
Final Thoughts

• Both male and female sexual orientation run in
  the family
• Biological studies often disturb many gays and
  lesbians. They believe it suggests that science
  is looking for the cause of homosexuality as if
  it were an illness.
• If we were to discover the cause for
  homosexuality, we in turn would find the cause of
  heterosexuality.
• Are gays to be tolerated only if they are born
  that way?