There are some women who post threads that also specifically ask for a "woman-only response" which, I think, is totally understandable. Our bodies function differently and there's no way a man can give as proper or accurate a description/definition/explanation as a woman can (unless he's a gynecologist or something, but even then, he's simply speaking from second-hand experience, not first-hand).
Likewise, the same goes with some of the questions men pose to women, albeit a very small percentage of them. If a man asks a question about pregnancy because he wants to better understand what his wife is going through and how he can better assist her, then I think, that too, is perfectly acceptable. Men don't know pregnancy like women do. He can pretend all he wants that he knows what the cravings are like and all that jazz, but his opinion will never be quite as useful or correct as a woman's (well, most cases anyway).
Perhaps simply stating a preferred response from a desired gender would be the best solution. That shouldn't really bother anyone.