Emily Oster

2 min Read Emily Oster

Emily Oster

Does Marijuana Use Affect Sperm?

Q&A on sperm and TTC

Emily Oster

2 min Read

Any updated information on pot and sperm counts?

—Anonymous

There is continual speculation that marijuana consumption could lower sperm counts or, more generally, impact sperm. It’s not just the number of sperm you have that is relevant. It’s the quality — their shape, how good they are at swimming, etc. There are lots of things that affect sperm. Tight underwear, for example.

In mice, marijuana exposure is linked to infertility. There are biological reasons to think the link might be in people too. There is a 2021 review that pulls together what we know about marijuana consumption and sperm parameters. It does conclude that marijuana is linked to lower sperm counts and worse sperm quality.

However: the evidence is limited. Part of the problem is that sperm quality evaluation isn’t something that people typically do for fun; it usually happens as a result of an evaluation for subfertility or infertility. What the data can show is evidence of a correlation between pot and sperm among a set of people who are experiencing infertility. It’s not clear that this applies in general.

In principle, one could imagine doing an evaluation of this question in healthy men, especially since sperm gets regenerated over time. You could take a cohort of regular marijuana users and encourage a “treatment group” to abstain for a certain period, and measure sperm over time. I am not aware of any studies that have done that. What we can say for now is that the link seems possible and, if you’re struggling with male infertility, it is worth evaluating.

Community Guidelines
A positive pregnancy test is seen resting on top of a calendar.

Nov. 17, 2022

7 min Read

How Long Does It Take to Get Pregnant?

Some answers on first and subsequent pregnancies—pulled from your survey data

A line graph with pink, yellow, and blue dots representing life's ups and downs.

Jul. 12, 2022

2 min Read

Wins, Woes, and Finding Hope

We’re back with your parenting wins and woes. Whether you’re flying high or feeling low this week, remember that you’re Read more

Two mothers smile at their new baby smile.

Jun. 2, 2022

6 min Read

Three Books You Might Really, Really Need

Queer parenting, infertility and a gentle approach to cleaning