It is referred to as gay gene(s) because there could be more than one and genes regulate everything. From the polyploidy trait of eye color, whether or not you will be a thrill seeker or to skin color. There are in fact splice variants for skin color. The POMC [[url=http://omim.org/entry/176830]http://omim.org/entry/176830] (MSHR, α-MSH, β-MSH, γ-MSH gene interacts with the melanocortin gene superfamily (MC1R [[url=http://omim.org/entry/155555?search=MC1R&highlight=mc1r]http://omim.org/entry/155555?search=MC1R&highlight=mc1r] (See 4 allelic variants), MC2R, MC3R, MC4R, MC5R) via a gene-protein-protein-gene regulatory network. Why shouldn't there be a genes which regulate whether you are gay, straight, or bisexual. There is an interesting book by the Oxford University Press, I have a copy in pdf if you wish to read it. [[url=https://global.oup.com/academic/product/gay-straight-and-the-reason-why-9780199737673?cc=ca&lang=en&]https://global.oup.com/academic/product/gay-straight-and-the-reason-why-9780199737673?cc=ca&lang=en& The book also points out that there are physiological differences such as having different sizes of the INAH3 in the brain [[url=http://www.ncbi.nlm.nih.gov/pubmed/18980961]http://www.ncbi.nlm.nih.gov/pubmed/18980961]. They point out a relationship between handedness with sexuality and the ability of gay people to suss out other gay people better than straight people can i.e., the famed "gaydar". To answer your question they have identified gene candidates for homosexuality specifically. As I stated, the keyword is "candidate", they are still doing research.
