I think there is the general stereotype that people have of lesbians, which is probably a holdover from the days of fear mongering about how we are evil and were coming to take away your women. Another stereotype (at least on t.v) is that all we want is to have babies. Lots and lots of babies.
Funny story (at least, I think it is) - back when I was still at a Big 4 firm, a co-worker and I used to play a game with other people on our team. We called it "Guess the Jew, Guess the Lesbian". Both of us were Jewish, but at the time we played the game, I was the only lesbian. What is funny is that since we phrased the game as guess one, guess the other, no-one ever clued in as to the fact that one of us could be both, so I was always chosen as the Jew, while my friend was the Lesbian. We both had long hair (mid-back), I just wore mine loose, and she wore hers back in a ponytail. Also maybe the fact that she mostly wore black suits, while I had a navy one AND a light gray one (what can I say, I was an adventurous auditor.) It's even funnier now that she's come to terms with her sexuality as we both identify as lesbians and Jews. Oooh, I'm going to call her up and see if she's interested in doing that sometime soon.