If homosexuality is determined by genetics, why does it still exist?

Question

Genes are only spread when people reproduce, so if homosexuality is genetic, how does it still exist? It doesn't really seem to follow the principles of Darwinism.

Answer 1

For a start many homosexual men and women have children. There is nothing to stop gay men and women having sexual relations with the opposite sex or even marrying - and many do. When homoseuality was illegal, most gay men and women got married and had children. It is only very recently that they can live openly as gay.

In nature homosexuality has been observed in more than 400 species and the common thread is that families with homosexual members have greater reproductive success as the homosexual couple help feed and defend the young. Even today, gay men and women help their siblings with their children in many ways. As far as genes are concerned, helping your brother's children is the same as helping your own.

Answer 2

Probably the same reasons why Muscular Dystrophy doesn't die out.

I am not a geneticist, but I think the way MD continues on is that mothers can carry the gene for MD but not be affected. In a carrier mother, she can expect in each pregnancy with equal probability each:

Non-carrier daughter
Carrier daughter
Unaffected son
Affected son

I won't try to recall the idea on my own, so I will point you to http://en.wikipedia.org/wiki/Sex_linkage for this idea.

Basically, the MD gene can live on through females. However, I can't really say the same for any gene responsible for sexual orientation. It could have a genetic cause or influence, or it could be tied to prenatal hormonal exposure, or a combination of both.

(Note: any comparison made of being gay to Muscular Dystrophy DOES NOT IMPLY that I consider it to be a disease or disorder or syndrome)

Answer 3

If the "Gay gene" actually existed; it wouldn't fit into today's society easily because,
If it was dominant (Same way as Huntingtons Disease), that would mean you'd have to have 1 gay parent to have 50% chance of being gay.
If recessive (Same way as Cystic Fibrosis), it can pass without your parents being gay, but it takes two parents with a recessive Gay gene to give you 50% chance.
The reason these two styles don't work is that the numbers don't add up for the first one; and there's other flaws in the recessive one, that's why it's usually not believed to be genetic.

It could be genetic; in the way JK said above.

Answer 4

Just because I'm gay doesn't mean I'm incapable of reproduction.

The animal world is filled with examples of animals who mate only to perpetuate the species but have the majority of sexual encounters with their own gender.

So I don't think anything about homsexuality necessarily negates Darwin's work.

Though I have no idea if there really is a genetic cause for homosexuality, either.

Answer 5

It exists because there is nothing wrong with homosexuality.

It could be that having at least one homosexual child would be preferred to take care of elderly parents since they would not have children of their own; it could be that homosexual men could stay with women of the tribe while straight men went hunting, providing strength to defend the women while not being a sexual threat to the women while their mates were hunting; it could be a form of population control so the species would not die out by not having enough food to feed everyone and their children; or it some other unknown reason or a combination of reason.

Scientific researchers who specialize in human sexuality have shown that homosexuality is linked to biology and genetics.

An October 2004 scientific research publication stated that scientists at the University of Padua have found that women tend to have more children when they inherit the same genetic factors linked to homosexuality in men. This fertility boost more than compensates for the lack of offspring fathered by gay men, and keeps the “gay” genetic factors in circulation.

A 2005 study reported genetic scans showing a clustering of the same genetic pattern among gay men on three chromosomes - chromosomes 7, 8, and 10. The regions on chromosome 7 and 8 were associated with male sexual orientation regardless of whether the man got them from his mother or father. The regions on chromosome 10 were only associated with male sexual orientation if they were inherited from the mother.

A study published in Human Genetics in February 2006 examined X chromosome inactivation in mothers of gay sons and mothers whose sons were not gay. Researchers found extreme differences between women who had gay sons and women who did not.

Another 2006 scientific study said that researchers have known for years that a man's likelihood of being gay rises with the number of older biological brothers, but the new study found that the so-called "fraternal birth order effect" persists even if gay men were raised away from their biological families. The older-brother effect was constant regardless of whether the men were raised with natural, adopted or stepbrothers. It also didn't matter if they weren't raised with their biological mothers.

Answer 6

Actually homosexuality works very well within evolutionary theories.

You have to understand first though that evolution is not about 'individuals' passing on genes. Its really about populations passing on genes.

For instance. Lets say I live in a small tribe in africa, 50 thousand years ago. I'm a man and I have a brother and we live in an area that has recently had some famine or disease. Many women died and so there not a lot of women to chose from for mates, but more than a few males trying to mate. My DNA is very, very, similar to that of my brother, to the point that in evolutionary terms it doesn't much matter which one of us procreates as long as one of us does.

Now if both of us are straight, we, as individuals are in direct competition for mates. This could lead to jealously or even outright violence between us, which might lead to neither one of us reproducing.

Now lets say my brother is gay. As a member of my family we have a bond, we help each other, but if he's gay, we're no longer competing. So I get the benefit of having him around and helping me, AND he's not in competition with me, so if I need help getting a mate, he would have every reason to help me, rather than hinder me.

Answer 7

ever heard of recessive genes? No I am not saying it is a mental illness or anything like that, but one possibility is that it is simply a recessive gene. It occurs in a number of species as well. Alternate theories suggest that it is precongenital and related to though not the same as transsexuality and transgenderism, but this is merely speculative. One way or another it is a natural occurance.

Answer 8

Because its determined by the amount of female / male hormones so there's the chance of someone being homosexual from any heterosexual procreation, and that"s why it continues. I would think so anyway.

Answer 9

I can guarantee you i'm not pretending, or ever made a choice.

When I see a hot guy I get weak in the knees and start breathing faster.

Answer 10

Gay people can donate sperm to sperm banks too you know, and there is a possibility that it also ISN'T genetic