This Boing Boing post where Chewbacca gropes Leia reminds me of one of the things which bugs me about aliens in some scifi:
Why would little green or grey men / wookies / reptilian warlords / multi-ton slugforms want human women? I would think that our women would be too small, soft, pink, and hairless for any of the above—and I'd assume the scent would be all off, not to mention the arrangement of orifices. And yet, it seems like scifi is rife with aliens who just can't get enough, embodying caricatures of the human id.
But, I just wouldn't think that human females would set off any alien sexual response, since I'd imagine that response would have evolved to encourage reproduction with their own kind. Unless, of course, these aliens fall into categories of sexual deviancy in their own societies—analogous to our dendrophiliacs, perhaps.