Source: Holland Davis, "Identical twin studies prove homosexuality is not genetic." 13 May 2013.
Source: Whitehead, N. E., Ph.D., "The Importance of Twin Studies." Narth.
Source: Whitehead, N. E., My Genes Made Me Do It.
After years of trying to prove a genetic basis to homosexuality, the evidence is mounting that homosexuality is not caused by a person's genes.
"Eight major studies of identical twins in Australia, the U.S., and Scandinavia during the last two decades all arrive at the same conclusion: gays were not born that way. 'At best genetics is a minor factor,' say Dr. Neil Whitehead, PhD." [Holland]
"'Because they have identical DNA, it ought to be 100%,' Dr. Whitehead notes. But the studies reveal somthing else. 'If an identical twin has same-sex attraction the chances of the co-twin has it are only about 11% for men and 14% for women.'" [Holland]
"'No one is born gay,' he notes. 'The predominant things that create homosexuality in one identical twin and not in the other have to be post-birth factors.'" [Holland]
"A significant twin study among adolescents shows an even weaker genetic correlation. In 2002 Bearman and Brueckner studied tens of thousands of adolescent students in the U.S. the same-sex attraction concordance between identical twins was only 7.7% for males and 5.3% for females -- lower than the 11% and 14% in the Australian study by Bailey et al conducted in 2000." [Holland]
It appears that the preception of life-events has a greater impact on whether a person sees himself as a homosexual. In the study by Bailey, "His team asked non-concordant identical twins (one was homosexual, one not) about their early family environment, and found that the same family environment was experienced or perceived by the twins in quite different ways. These differences led later to homosexuality in one twin, but not in the other." ["Importance"].
What is even more interesting is that the same set of research defeats another common myth: that homosexuals can't change.
"In the identical twin studies, Dr. Whitehead has been struck by how fluid and changeable sexual identity can be. 'Neutral academics surveys show there is substantial change. About half of the homosexual / bisexual population (in a non-therapeutic environment) moves towards heterosexuality over a lifetime. About 3% of the present heterosexual population once firmly believed themselves to be homosexual or bisexual.'" [Holland]
Interestingly, the change is mostly one-directional. Having a same-sex attraction has a strong tendency not to last.
"About half of those with exclusive SSA move towards heterosexuality over a lifetime." [My Genes].
"Most changes in sexual orientation are towards exclusive heterosexuality." [My Genes].
"Ex-gays outnumber actual gays." [My Genes].
"Exclusive OSA is 17 times as stable as exclusive SSA for men and 30 times as stable as exclusive SSA for women." [My Genes].
"'Sexual orientation is not set in concrete,' he notes." [Holland].
Also of interest is that the changes occur without intervention through counseling.
"These changes are not therapeutically induced, but happen naturally in life, some very quickly." [My Genes].
The change is most noticeable in the teenage years.
"The fluidity is even more pronouced among adolescents, as Bearman and Brueckner's study demonstrated. 'They found that from 16 to 17-year-old, if a person had a romantic attraction to the same sex, almost all had switched on year later." [Holland].
"Most teenagers will change from SSA. In fact, in the 16 to 17 year age group, 98% will move from homosexuality and bisexuality towards heterosexuality. 16 year olds saying they are SSA or Bi-attracted are 25 times more likely to say they are the opposite sex attracted at the age of 17 than those with a heterosexual orientation are likely to identify themselves as bi-sexual or homosexual. 16 year olds who claim they are oppositee sex attracted will overwhelmingly remain that way." [My Genes].
"Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God. And such were some of you. But you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus and by the Spirit of our God" (1 Corinthians 6:9-11).