...or rather, getting them SLOOOOW.
Two weeks ago I covered a study on cannabis coming for mouse sperm. But that's mice, not humans, and most of it was in a dish. So what does it mean for PEOPLE? After all, mice don't spend most of their time mating on weed, while humans...well we DO spend a lot of time mating, and some spend a lot of time on weed, so that's got to intersect somewhere.
And here's where it does!
Whan et al. "Effects of delta-9-tetrahydrocannabinol, the primary psychoactive cannabinoid in marijuana, on human sperm function in vitro" Fertility and Sterility, 2006.
(Human sperm under a microscope! Cool, eh?)
It's easy to wonder why, exactly, you'd want to look at effects of delta-9-tetrahydrocannabinol (d-9-THC), the active ingredient in marijuana, and why it affects sperm. I mean, all sorts of other things, sure, but sperm? Why should we care?!
But it turns out that the human reproductive system could be much more sensitive to the cannabinoid class of drugs than you might think. There are receptors that d-9-THC can hit (cannabinoid receptors) in the male sperm and testes, and in the female uterus (though no one ever seems to investigate females for this kind of thing). And this, combined with the high rates of at least occasional marijuana use, means that people want to know what effect cannabis has on your semen.
Also, semen on drugs. I mean, that's kind of awesome.
This is your sperm.
And this is your sperm on DRUGS!!!
And this study has something even better going for it: computer assisted semen analysis. Yes. This makes me think of some sort of bizarre Japanese robotic sperm donation center or something.
Anyway, the authors of this study wanted to look at your semen getting high. So they collected semen in the usual manner. This usually means asking people at the fertility clinic for an extra sample from people who turned out normal. Just a few minutes in the bathroom with a laptop and a cup!
When the semen comes out, the scientists spin it down in a centrifuge, to separate out the sperm from the other bits. Put it in a dish, added some THC (recreational and therapeutic concentrations), and had the computer look at the sperm function.
You can see here that there's a dose dependent reduction in sperm motility, the little guys swam slower in the presence of THC.
They also looked at the effect of THC on the acrosome reaction, where sperm open up the caps at their tips to release enzymes and break into the egg. Again they saw dose dependent decreases in acrosome reaction. From this, they conclude that cannabis might be bad for male fertility.
Me, I'm not so sure. Sperm in a dish are not sperm in your junk, and THC applied in a dish is not THC coming in slowly through bloodstream exposure. And the decreases at the lower doses? They are pretty small.
There's also other stuff about sperm that isn't accounted for. For example, what happens when THC goes away? Do the sperm recover? Sperm normally turns over every 60 days or so. So what about long term?
And then of course, there's the really important question: when you're on cannabis...do you really feel like testing your swimmers? Most people probably aren't actively trying to successfully reproduce while high. So what we REALLY need to look at are the effects of cannabis use on your sperm AFTERWARD. And this study doesn't look at that.
So I can't tell you whether cannabis smoking affects your sperm. What I can tell you? Don't put THC on your sperm in a dish. It makes them lazy.
Whan, L., West, M., McClure, N., & Lewis, S. (2006). Effects of delta-9-tetrahydrocannabinol, the primary psychoactive cannabinoid in marijuana, on human sperm function in vitro Fertility and Sterility, 85 (3), 653-660 DOI: 10.1016/j.fertnstert.2005.08.027