To start with the literal truth: Men can indeed speak about issues pertaining to women, because (some) men do speak about such issues, which proves that they can . The question is how authoritative, how credible, about those issues a man can be. I think that will depend on the issue. An appropriately trained male researcher can speak with authority about (for example) the long-term health effects of this or that means of female contraception. But if the issue is more "experiential" or "phenomenological" -- such as "What does it feel like to be a female victim of workplace sexual harassment?" -- then it seems clear that any male has at least a burden of proof to discharge before we should regard his statements as authoritative or credible. I'm not saying that this burden can't possibly be discharged, only that it exists. (Clearly, I assume that speaking credibly about whether a man can be authoritative on issue X doesn't require me to be an authority on issue X itself.) For my answer to a...

What counts as a cause is certainly a philosophical question, and although both laypeople and scientists often confidently talk about causes, philosophers are far from unanimous about the correct analysis of the concept of causation. It's a matter of considerable controversy: see, for example, this SEP entry . But if we achieved a precise enough and plausible enough understanding of cause and a precise enough and plausible enough understanding of the concept homosexual (perhaps easier but by no means easy), then I think the question of what causes homosexuality would be purely empirical rather than philosophical. It may not be a purely biological question (again, assuming we understand biological precisely enough), but I don't think it would be, at that stage, a philosophical question. Still, lots of philosophical work would need to be done before the question became well-enough understood to be answerable empirically. Or so it seems to me.