Sep 042013


While there is still much debate on the exact causes of homosexuality and a “gay gene” remains elusive, biological scientists agree that there is a strong genetic influence to homosexuality.

World-wide, there is a general consensus that exclusive homosexual orientation occurs in between 8-10%,

Are there More Homosexual Males than Females?

Yes.  It is estimated that there are twice as many men than women who claim they are homosexual.

Does Homosexuality occur in Nature?

Yes. Biologists,such as D.P Barash, have discovered forms of homosexuality in many other animal species to which humans are related to varying degrees, from baboons to dolphins and from penguins to worms.   (Barash, D. P. (2012). Homo Mysterious: Evolutionary puzzles of Human Nature. Oxford University Press.)

David Barash (in the above book) offers a number of scenarios for homosexuality.images-6

  1. Kin helping

Barash suggests that by refraining from producing off-spring themselves, homosexuals can invest more time and resources in rearing the offspring of close relatives with whom they share portions of their genes.

On the island of Samoa found that male homosexuals invest significantly more than male heterosexuals to support their extended family, and that they are fully accepted members of their societies.

2. Group selection

It is also possible that homosexuality emerged because it produced benefits for the entire group. Homosexual had no children, thereby, not exhausting resources such as food and water.


3. Sexual attraction

A third possibility that homosexuality–promoting genes were selected for because of women’s sexual preferences. The argument is that some women may have been favorably disposed towards homosexually inclined men because of their social, cooperative and empathic qualities. Thus, forming partnerships with those men may have ensured better care for children

4. Balanced selection

A fourth evolutionary explanation for the stable frequency of homosexual genes in human populations is that these genes provide some ulterior benefit. The argument is that although there is negative selection for homosexual genes (because their bearers do not produce as much offspring as individuals with heterosexual genes) there may be compensating benefits. For instance, if the genes for same sex preferences would also cause an individual to have a greater intelligence or a better physical health then there would be compensating benefits, leading to the spread of homosexuality genes in a population.

5. Sexually antagonistic selection

A final possibility is that homosexuality genes might produce different effects for males versus females. It could be that when homosexual genes reside in male family members this would result in them having fewer off-spring.

Yet when these same genes reside in the female family line they could result in them getting more offspring to compensate for the loss of fitness in males. There is some support for this

. One study found that the mothers of homosexuals had, on average, more children than mothers of heterosexual children. And the family members of the mothers’ line in homosexuals also sired more offspring. A review study just published in the Quarterly Review of Biology provides further support for this hypothesis. It suggests that particular (epigenetic) mechanisms that suppress androgens in female fetuses — that enable them to grow into more feminine bodies with feminine brains — also suppress androgens in male fetuses, which has the side effect of turning them into less masculine men. If these feminine women do better than the average female in getting more children such a mechanism could result in the propagation of homosexual genes.

These are some of the evolutionary hypotheses that are out there to support the relatively well-established scientific claim that homosexuality is a natural (normal) sexual orientation. More research is needed and hopefully in 2013 scientists will come closer to solving the mystery of homosexuality.

The biological science of homosexuality suggests that rather than discussing how we feel about homosexuals and how society should treat them, we should ask ourselves why homosexuality exists and what its functions are (or were).

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