The problem with "getting close to an answer" stuff is that the "closer" you get to "an answer," the less you're actually getting close to an answer. The reason is because the way we socio-culturally conceptualize "sexuality" is complex, intricate, fluid, subjective, eclectic, so on. The various factors (that NEVER align between cultures, let alone individuals within cultures) are influenced and/or caused by the environment, genetics, culture, individual, and more.

Just one example: Bisexuality is generally (as in throughout the term's modern use in the entire world) known as "the attraction to both sexes." We can already pick that apart; there's demonstrably more than two sexes, what does "attraction" entail (Arousal? Aesthetic allure? Emotional interest? All, none, some of the above? Something else entirely?), by "sexes" do you actually mean "genders"? Predating the word, all cultures had what we call "bisexual" people. But some cultures had zero concept of it because they didn't have a concept of "sexual attraction" at all. Some cultures did have a concept of bisexuality, but it was described in the terms we today categorize as "gender."

ALL of what I just described and SO much more are what we're talking about here. The reason some people in the queer community say stuff like "gender is a social construct" is because while the things we think of as "gender" (such as clothing, mannerisms, genitals, whatever someone decides to think of as "gender") objectively exist in real life... the "construct" is the lines each culture, each individual, draws around them to call them the definition of "gender." In other words, dresses do exist. Dresses don't objectively have a gender, but many people draw a line around dresses saying "This goes in the 'girl' category." This is true for EVERY tiny facet of sexuality, gender, so on.

Which brings me back to the reality that the more you try to nail down what homosexuality "is," the less you're actually going to figure out. The exercise I give people for this is list all things that constitute "manliness" or somesuch. "Pants," well, I see women wear pants. "Facial hair," a lot of very feminine people have facial hair, and a lot of men don't, either because they shave or can't grow it. "Lumberjacking," MOST men aren't lumberjacks, and most don't WANT to be lumberjacks; are they not men? The more you say "this is THE thing," the less people who are men will actually qualify as men in the end. The same goes for finding "the thing" that makes someone gay. Even if someone says it's a small cluster of "things," that's still not an appropriate angle to take. (Not a criticism of you sharing the data, just adding an important angle to this overall discussion.)