Do we know that pre-ejaculate fluid can contain active sperm? Yes, we do. We also know that there are far, far less sperm in pre-ejaculate -- when there are any at all -- than there are in a full ejaculation: a full ejaculation contains as many as 100 million soperm, whereas when sperm is in pre-ejaculate, it's more like a few million. But it only takes one active sperm and a few hundred helper sperm to create a pregnancy, so there are more than enough sperm in pre-ejaculate when sperm are present in it to make that happen. We also know that withdrawal isn't a very effective birth control method, and that enough people report using it perfectly -- withdrawing well before ejaculation -- and still becoming pregnant (including myself as well as a close friend of mine, for a personal perspective), that we'd be remiss to rule out pre-ejaculate as a pregnancy risk. Bear in mind that during the Baby Boom in the United States -- a period in history when we had more births than any other -- that withdrawal was the most common method of birth control people were using. Too, unprotected sex, period -- ejaculate or no -- poses risks of all sexually transmitted infections, which should be just as great a concern as pregnancy. And pre-ejaculate can transmit the HIV virus just as much as full ejaculate can. So be careful & you should really use protection, no matter how much you trust each other. Keep good communication with her, & if she misses her period - wait 2 weeks, & have her take a pregnancy test. Good luck!