The general consensus seems to be that since men aren't women, they can't speak about or fully understand the issues pertaining to women. I once read an analogy that tried to equate this logic with someone telling a veterinarian that since he isn't a cat, he cannot speak about the issues pertaining to cats. But since veterinarians do speak about cat issues, then it is safe to assume that men can speak about women's issues as well. Does the analogy work? Can men speak about women's issues?

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...

Can a white male ever legitimately speak about racism or sexism?

As a white male myself, I guess I'm answering your question in the affirmative by even presuming to post an answer to it at all. Surely the question you asked is so broad that no one could reasonably answer it in the negative. Racism exists: some people or practices are racist. Sexism exists: some people or practices are sexist. There: I've said it, and I defy any reasonable person to deny my assertions or call them "illegitimate." Now, it's a harder and more interesting question exactly how much a white male can say about racism or sexism without losing credibility on those issues, but I'm inclined to think that a white male could, in principle, become the world's foremost authority on racism and sexism, and the burden of proof would rest with anyone who said he couldn't speak legitimately on this or that particular aspect of those issues: we'd be owed an explanation why not.