I don't have a lot of knowledge of the Levay experiment in which the structure of a hypothalamic nucleus was found to be morphologically distinct in straight men, women, and gays. I only know what I've read, and I have not read the primary sources. They are supposed to be significant for the impact the conclusion has on homosexuality being a choice. Because some believe this topic actually has some merit, I googled some responses, and they sound like a mix of legitimate and stupid concerns, but you can find those as easily as I can.
My impression is that nobody should be surprised if there are brain morphology differences between gays and straights and there should be no surprise if there are genetic contributors to personality and other aspects of human identity. Big fat hairy deal.
All this scientific effort will have shown that people are indeed not "created equal" but that we have to work within our unique set of personal circumstances. It's not fair, true, but a perceptive toddler could conclude as much about life. Hell, make that an UNperceptive toddler. You deal with it the best you can rather than expecting the world to somehow make it up to you by redoing expectations of behavior and morality.
That's not to say that there aren't plenty of non-biological issues related to the morality and social circumstances of gays. But the biological arguments I've never found compelling in the least.
At the same time, the biological experiments wouldn't be as big a deal if it weren't for the monumentally stupid idea that sexual attractions are chosen. But, neither the far right nor the far left feel served by putting the issue in just such precise terms. It's better to discuss the idea that "being gay" is chosen so that both sides can indignantly battle for the broad political implications that follow from affirming or denying that statement, vague as it is.
Misinterpreting the science for a political agenda, most often inadvertently, is the standard practice. The gay rights movement (bless their little hearts) have bought in to the philosophical approach that the end justifies the means, a hair slow in noticing that strong advocacy for aims popular to some gays is harmful to other gays. Much (if not all) of the published scientific data is influenced by bias at some point in the scientific process (largely from advocates--sometimes the scientists themselves), despite all the best efforts to mitigate it (or disguise it).
There's a fair chance I just don't get why all this science has much meaning. But I sort of think the odds are in my favor that it's the scientists and political pundits who just don't get how much the biological science doesn't matter on this topic and other matters of morality.