If homosexuality were significantly influenced by genes, it would appear in every culture, but in twenty-nine of seventy-nine cultures surveyed by Ford and Beach in 1952, homosexuality was rare or absent. It was very rare in the Siriono, even though there were no prohibitions on homosexual relationships in that culture. The researcher observed only one man displaying slight homosexual traits but apparently not sexually involved with another man. Homosexuality appears to be rare among Orthodox Jews, so much so that learned rabbis, the interpreters of Jewish law, usually allowed men to sleep in the same bed, because likelihood of sexual contact was considered negligible. Kinsey also found very low homosexual incidence among Orthodox Jews...

This evidence comes from missionaries who commonly spend 25 years of their lives living in one culture, far more than almost any anthropologist....Overall they can be considered as reliable witnesses. For example, in contrast to groups like the Sambia in the New Guinea highlands, where homosexuality was compulsory, only about 2-3 percent of Western Dani (also in the New Guinea highlands) practiced it. However, in another group of Dani who were genetically related, homosexuality was totally unknown. Missionaries report that when they were translating the Bible into Dani for this group, their tribal assistants, who knew their own culture intimately, were nonplused by references to homosexuality in Romans 1; they did not understand the concept. Another missionary, with the same group for 25 years, overheard many jests and sexually ribald exchanges among the men, but never a single mention of homosexuality in all that time. When Dani went to help with missionary work among the Sambia, they were astounded at some of the homosexual practices they saw for the first time. Although it is always difficult for a foreigner to be completely sure whether a rare and stigmatized behavior exists, it is certainly true that if three such different experiences of homosexuality can occur in groups of people so closely related genetically, genetically enforced homosexuality is an impossibility.