sorry, but something as big as this should be a proven scientific fact.
if its not scientific, then how do we know that its not an impluse that is caused by improper upbringing followed by a lifestyle of bad choices.
If it is not a medical condition brought on by specific differences in the body, then it must be a choice.
Research is still ongoing, however scientists who are allowed to continue with their research without their funding disappearing, believe it's not just "one" gene.
Is there a homosexuality gene?
And since nobody likes to click my links:
"During the past several decades, scientists have discovered some interesting patterns that may point toward genetic causes of homosexuality. Among the findings is that male homosexuality appears to be inherited more often from the mother than the father (Pillard). Also, natural selection might maintain a gene that may decrease the fecundity of one sex because the same gene also increases the fecundity of the other sex. In fact, recent data shows that female maternal relatives of gay men have higher than average reproduction capacity (Camperio-Ciani). "
-and-
"Gavrilets and Rice identify two main factors that may explain the polymorphism of a gene (and how the gene spreads): overdominance and sexual antagonism. Overdominance refers to phenotypes that come from heterozygous genes, and the advantages promoting genetic variation. Sexual antagonistic traits are those that are advantageous in one sex, but may cause homosexuality in the other sex. For a variety of different gene inheritance patterns, the scientists provide mathematical models that require, in essence, that the benefits for one sex must outweigh the costs for the other sex."
Here's additional research articles on this subject:
CAT.INIST
http://www.tiem.utk.edu/~gavrila/PAPS/h.pdf
Mother
Here's one more piece of information:
Homophobia (from Greek ὁμο homo(sexual), "same, equal" + φοβία (phobia), "fear") is a non-clinical term[3][4] used to describe the fear of, aversion to, or discrimination against homosexuality or homosexuals.[5][6] It can also mean hatred, hostility, disapproval of, or prejudice towards homosexuals, or homosexual behavior or cultures.[7] Homophobic is the adjective form of this term used to describe the qualities of these characteristics while homophobe is the noun form given as a title to individuals with "homophobic" characteristics.
Footnote 4 of Merriam Webster dictionary's definition defines homophobia as "irrational fear".