The question of pre-cum and sperm content seems to be in a debate. One article says there is no sperm in pre-cum, another says that the previous research's fluid collection methods were faulty. So is there sperm in pre-cum, or is that just another sex-negative scare tactic?
Which Is It?
The question of whether, or rather the assertion that pre-cum does contain sperm, certainly has been used as a sex-negative scare tactic, specifically as a weapon in the chastity wars. I wouldn't go so far as to write off the question itself as pure propaganda tool, though — it's a legitimate subject for scientific inquiry, and we are all about those.
While the interwebs present a boundless sea of sex information, sex "information," and purest balderdash, we have to watch where we're going. I've taken on this one at intervals for years, but needing a fresh fact-infusion I headed to PubMed, as one should. There I found that an andrology lab at Ben Gurion University in Israel seems to be doing all the interesting work. The lab collected pre-ejaculatory fluid from its premature ejaculation patients, another group referred to the lab for "excessive fluid secretion during foreplay" (this paper was nicely titled "Copious pre-ejaculation: small glands-major headaches"), and a control group of regular guys. All were sampled several times during foreplay, whatever that is, and after masturbation, and none had any sperm at all in the pre-ejaculatory samples. None. And no matter how many times those scare-tacticters warn credulous teens about it only taking one (true, but that One's chances of making it through the vaginal gauntlet and the Chamber Of Cervical Horrors to emerge victorious are almost as small as the sperm itself), even they can't make a claim that "it only takes none." None is none. None is good.
So ... we do have some science. We do have samples studied and found utterly devoid of sperm. We also have, of course, innumerable pregnancies blamed on those sneaky gland-lurking sperm. What are we to make of those? Some claimants are lying. Some failed to flush out the urethra with a nice healthy pee after the first ejaculation, which could certainly result in some loiterers being carried along by the next stream of pre-cum that happens by. And some are the result of "oopsies!" of various sorts, including undetected or unstoppable mini-ejaculations before the main event. None of this has ever succeeded in convincing me that withdrawal is unsafe or stupid or worse than nothing, as some of that scare-based literature would have it. It is, in fact, the precise opposite of "worse than nothing": it is in every way better than nothing. Kids who are taught that condoms leak and pills fail and withdrawal is worse than nothing end up using ... nothing. And that, my friend, is worse than anything.