Biology + Environment = Gay or Straight
They are not quite sure how it all comes together.
A variety of things point to someone being “more likely” to be gay, but none of the following are determinative:
- Gay men more often have a counterclockwise hair whorl
- Lesbians more often have a male pattern “longer ring finger/shorter index finger”
- Left-handed and ambidextrous folks are more likely to be gay or lesbian
- Boys with older brothers are more likely to be gay
- Twin studies suggest genes account for 34% to 50% of the reason why someone is gay
Genes, hormones, brain structure and womb chemistry all seem to play a role.
But maybe it takes a blending of factors to create straight or gay.
Why aren’t identical twins always the same sexual orientation?
I’d like to spend a bit more time discussing why identical twins don’t always share the same sexual orientation.
The blending of factors I just described might play a role. Some researchers have suggested that twins might get a different hormone distribution, depending upon their placement in utero, for instance.
Maybe epigenetics are a factor, too. When twins are born their genes are identical. But over time the environment adds information and affects gene expression, so that twins become less identical with age.
There’s also the question of admitting that you are gay. When twins are separated at birth, one twin might be more likely to admit — to himself or to others — that he is gay if he were raised in a more liberal home, for instance.
(Second in a 3-part series on sexual orientation.)
Posted on December 4, 2015, in feminism, LGBT+, psychology, sex and sexuality and tagged did you choose to be straight, feminism, LGBT+, psychology, sex, sexual orientation, sexuality. Bookmark the permalink. 28 Comments.