Iono. There's an argument to be made that not all males write good females, and not all females write good males. 

But I think I write both pretty well, and I've been laughed at in PMs for asking to RP with a girl looking for male partners.

So, in a perfect RP world it wouldn't matter. But as I'm convinced Twain had the right of it; humans are the worst, and far from perfect. =)