I mean, homosexual humans don't naturally have children, because it takes a female and a male to have children the natural way.
Not true. Homosexual people are perfectly capable of having children, physiologically speaking. A preference for one's own sex doesn't make it physically impossible to mate with the opposite sex, just undesirable. There is a difference between preference and behavior, in the same way that there's a difference between climate and weather. A place with a cold climate can still have the occasional warm day, and a person whose overall sexual preference is in one direction can occasionally choose to make an exception -- or feel obligated to do so. In societies where homosexuality was stigmatized, many gay or lesbian people got married and had children because it was expected, because they were hiding or denying who they were. In some cultures where it was more tolerated, it might still have been considered a social obligation to produce an heir regardless of one's choice of recreational partners; after all, some cultures make more of a distinction between recreational sex and procreative/marital sex than ours traditionally has, which is why many cultures have found it perfectly acceptable for married men to frequent prostitutes or keep concubines. Such a culture might tolerate people having same-sex recreational partners as long as they did their duty and produced offspring. They might not have enjoyed the process of procreating, but we often perform duties we don't enjoy. Preference is one thing, capability another.
Today, plenty of gay couples find ways to have children, whether by adoption, surrogacy, in vitro fertilization, or whatever. There's a big difference between whether you want to have heterosexual intercourse and whether you want to be a parent. GLB people in the past didn't have the range of medical options we have today, but it's likely that many of them still desired to have children, and thus may have bitten the bullet and done what was needed to make babies even though it wasn't their preference.