I'm a female-type person. I can't speak to anyone else, but I did make a post a while ago, and it was met largely with indifference and I wound up taking a (small) karma hit. This did a variety of things, some useful and some not, but one thing it hasn't done is encourage me to take the time to write another top-level post.

If I'm wandering around a large in-person gathering and I drift over to an interesting conversation and say something and get shot down - even if it's because I said something stupid - I'm more likely to drift away or at least shut up rather than continue to hang out with and seek approval from Those People Who Were Mean To Me™. "Drifting away" is much easier on the Internet, and if more women are giving up after making one or two poorly-received comments, that could easily explain the gender bias.

Possible solutions if I have the right idea (no idea how palatable they are to others):

1) Be more parsimonious with downvotes and generous with upvotes in general.

2) Attempt to draw out individual women Less Wrong ers on particular topics (solicited input puts one out on less of a social limb).

3) Identify who makes each vote on a comment or post, so people can identify Those People Who Were Mean To Me™ and not have to consider the entire Less Wrong community as a whole to be united against them.