I've got a female co-worker who talks about sex all the time and runs her mouth about all sorts of things. It's just when she's hanging out with other co-workers, nothing serious in and of itself, no flirting or harrassing or anything like that ... FWIW, that sort of idle conversation can be taken as creating a "hostile" work environment, or as harrassment. Work is supposed to be about work. If her chatter makes you uneasy, ask her to stop, please. If she doesn't, then complain to her supervisor.
I used to work at a K-Mart type store when I was in college. I was usually the only guy who worked evenings. There were usually 8-10 women working. The things they talked about in the break room made me blush. "Size" was only the beginning of their nightly talks.
Is it too late to sue 20 years after the fact! :)