Why hasn't homosexuality been eradicated by natural selection?

Since homosexuals don't usually have kids, their genes don't get passed on to the next generation. So it would seem that the gene for homosexuality ought to have died out fairly quickly. Then why is it still present?

Reply 1

Nightstar-27

12

maybe its recessive. There are also probably other factors like womb environment, hormones and brain structure. There are also theories that sexuality is a scale not a category. http://en.wikipedia.org/wiki/Kinsey_scale

(edited 11 years ago)

Reply 2

Harrifer

15

You're assuming it's genetic.

Reply 3

Pindar

16

Homosexuals for thousands of years have procreated with women because of social pressures.

The cause of homosexuality may have some genetic and environmental factors. Perhaps some may pass the genes (if they exist) whilst not necessarily having triggered them? Or possibly it could be mainly environmental and developed.

I point you to this:

Original post by thomaskurian89

Since homosexuals don't usually have kids, their genes don't get passed on to the next generation. So it would seem that the gene for homosexuality ought to have died out fairly quickly. Then why is it still present?

There are three possible theories, all with varying some evidence backing them. The truth is likely a combination of the three

1. Bisexuality transfer, or not being completely gay - homosexual genes (there are multiple) will be present in people of bisexual orientation, even those who are more heterosexual than homosexual, and so are passed on by those people's children. Genes linked to homosexuality may even be present in completely heterosexual people but not active or dominant, and so are passed naturally through the population

2. Stimuli theory - genes express themselves in different forms under different environmental stimuli. It may be that the genes linked to homosexuality expressed themselves in a different, evolutionarily advantageous or neutral way in the past, and that a change in stimuli associated with modern living (notably much larger societies) has caused them to express themselves in homosexual tendencies.

3. Fertility advantage - some of the genes linked to homosexuality actually primarily manifest themselves in enhanced fertility when present in the other gender. Genes that make guys more likely to be gay make their mothers/sisters much more fertile, and likewise with the fathers/brothers of lesbians. This means genes for homosexuality are conserved in the other gender as they have an advantage.

Reply 6

GoodbyeTSR

OP

13

Original post by najinaji

I point you to this:

Thanks for the video; it was quite informative. I love listening to Dawkins when he isn't talking about atheism. BTW, who is he talking to?

Reply 7

snozzle

12

It might not be determined by biological factors.

Reply 8

najinaji

18

Original post by thomaskurian89

Thanks for the video; it was quite informative. I love listening to Dawkins when he isn't talking about atheism. BTW, who is he talking to?

I agree. We don't get to see him talk about biology that much anymore, and it's a shame. And I don't actually know who the other man is. I've seen him before though, and I think he may have something to do with gay rights in the US.

Reply 9

EonBlueApocalypse

13

Original post by najinaji

I point you to this:

Was about to post this, I love how Richard Dawkins says 'sneaky ****er' .

Reply 10

ajensen

As a psychologist I'd advise people to take the interactionist approach here. Homosexuality may have genetic influence but in my opinion, this is paired with environmental stimuli that socially 'nurture' an individual into becoming homosexual.

Reply 11

Emilii

Either the natural selection theory isn't all that accurate or the homosexual people aren't all that homosexual. I would think that even if a person is homosexual they would have to want to have sex with a person of the opposite sex. How could anyone be not even duly be curiuos about it and not experience that? It should be on everybody's bucket list lmfao

(edited 11 years ago)

Reply 12

GeorgetheAug

Just because it's "Not a choice" does not mean it's 100% genetic/biological factors.

Reply 13

maturestudy

12

Original post by thomaskurian89

Since homosexuals don't usually have kids, their genes don't get passed on to the next generation. So it would seem that the gene for homosexuality ought to have died out fairly quickly. Then why is it still present?

Sexuality is not a binary function. People lie within a spectrum and can have different preferences at different times and in different situations. Many homosexuals have children; either through desire to nurture or social pressure. However, that is not the main problem with your argument.

Although there is some evidence for a genetic component of sexual orientation, the research suggests that homosexual traits are passed from a mother to her son. Straight women pass the homosexual trait on to there sons - there is no evidence that the gene is passed from a homosexual man to son because the gene lies on the X chromosome (men pass their Y chromosome on to sons).

In any event, the genetic element would only explain a minority, suggesting the others are gay due to social factors.

Reply 14

Mr Dangermouse

18

Was going to say that about straight women passing in the gay gene.

Reply 15

mmmpie

12

There are other factors besides genetics.

Environment in utero, for example. The more older siblings you have the more likely you are to be gay.

Bisexuality?

Original post by Nightstar-27

maybe its recessive. There are also probably other factors like womb environment, hormones and brain structure. There are also theories that sexuality is a scale not a category. http://en.wikipedia.org/wiki/Kinsey_scale

This. Bisexuality may be linked to homosexuality and gay men might have been used to look after the women when the macho men were out hunting and a man who swings boths ways could have pretended to be gay and sexed up the women when the other men were out.