And I say culture because that is the context in which we, as conscious organisms, would learn how to employ dialectics as a conceptual framework.
That isn't to say that homosexuality arises from the cultural sphere, as I am currently of the suspicion that there is a scientific basis for sexuality being biological, namely that it would have a genotype or maybe even some sort of phenotype somewhere. Just my working understanding of the science, for whatever the science may be worth.
A Sapolsky lecture at Stanford mentioned a study of some such phenotype, but I forget if it was a brain lobe shape or something else. Anyway it was said to conclusively correlate with self-reported sexuality, and was referenced jokingly on shirts sold at a pride event somewhere. I can track down the mention of it, if necessary.
That said I presume the self-reporting of the sexuality was likely parameterized under binary categories of homosexual and heterosexual, which may not be the case. If so, it could have conceivably skewed any conclusions drawn from it.