10 Facts that you should know, in order to answer the genetic-linked theory.
1) Non-twin brothers of homosexuals should share the same proportion of genes as fraternal twins (look previous discussion); however only 9% of them were homosexuals as compared to fraternal twins of 22%. Moreover, BAILEY & PILLARD found that the incidence of homosexuality in the adopted brothers of homosexual (11%) was much higher than recent estimates for the rate of homosexuality in the population (1-5%). In fact it was equal to the rate for non-twin biological brothers. This study clearly challenges a simple genetic groundless assumption & strongly suggests amongst others, environment contributes significantly to sexual preference.
2) A 1999 study done by neurologist George Rice found no evidence for homosexuality in the genes thus disproving earlier claims of biologist Dean Hamer that he found a specific gene for homosexuality in the X-chromosome that is inherited from mothers. Though Hamer stated that he had repeated his study to confirm that the same DNA sequence appears in the genes of homosexuals, his research had not been replicated by other scientists.
3) Many scientists have claimed that homosexuality is rooted in biology, but surprisingly enough, much of the research has been conducted by scientists living in homosexual lifestyle.
4) Homosexuality (i.e. Lesbianism) reduced reproduction, and should have disappeared long ago if there was a genetic linkage.
5) Ex-homosexuals do exist. If, homosexual preference were in the genes like human racial characteristics i.e. the skin color, change could not be possible. It is therefore clear that sexual preference is not UNCHANGEABLE trait. People learn their sexual preferences & orientations.
6) If homosexuality were biologically determined, it would have been practiced in all countries of the world. However, as is well-known, in some communities and tribes in Africa and other parts of the world, homosexuality is totally absent or so rare that the rural inhabitants may get the shock of their lives when the practice is described to them!
7) A female’s bare breast are sexually stimulating to Westerners and to many other cultures, but to men in some tribes in south of Sudan and Indonesia they are simply a couple of baby milk bottles, so women do not even bother to cover them up. In contemporary Mauritania, and in the Arab Northern Sudan of the 30s and 40s, obesity was greatly appreciated as one of the major attributes of female beauty. So the question is, do men’s sexual inclinations toward particular features have any genetic-linked supports? The answer is NO. Sexual preference is learned and not acquired.
8) It is obvious to any reasonable scholar that the Western gay liberation movements and scientists who support them are staging all this hereditary balderdash to support their cause. Otherwise, why do we neither hear of genetic link to pedophilia or sexual relations with children, nor bestiality, in which the deviant uses an animal for a sex partner. Certainly, the difference between heterosexuality compared with sexual relations with animals and children is much greater than the difference between it and homosexuality. This should have presented a more convincing justification for genetic aetiology. However, no group has taken such a stand since animals cannot speak for themselves and pedophilia is against the law!
9) Why homosexuality is so rampant in prisons, army camps and boarding houses of male students in remote public schools? Are those homosexuals co-incidentally ‘locked’ in the same place? This does not make sense at all. The only reason that could explain this; homosexuality is learned & practiced more common in places where large groups of males have no choice but to live away from females for a long period of time. It has nothing to do with genes.
10) The last & yet the most important one is, if homosexuality is biologically determined, then it is God who created this ‘preference’ in gays. If he then punishes them with mass destruction, as in Sodom, or severe sanctions, as in Shariah law, then no action can be more unjust than that & we Muslim believe God is far from injustice.
Malik Badri. “The AIDS Crisis: A natural product of modernity’s sexual revolution”.
Dr Muftie Allie Haroun Sheik. “Sexual Issues In Modern Era & Its Solution In Islam”. ADAM Publishers
Text Book on Psychology under the topic of Sexual Orientation.
 Byne, William, “The Biological Evidence Challenged” in Scientific American (1994)
 Another research done (by Hamer) tries to prove maternal genetic link on X chromosome in homosexuals (not discussed in details here).
 Rice, George, “Absence of Linkage to Microsatellite Markers at Xq28” in Science (1999)