system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is it about Johnson & Johnson's baby powder that could cause ovarian cancer?

Considering the decision today that J&J has to pay a massive fine to claimants regarding their baby powder reportedly causing ovarian cancer, I'm unsure about the science behind the claim.

What's in talc powder that could be risky? Are the same risks concerning men who use the powder to dry their groin area? 

Thanks!
gpt
Scientist here. The science behind this talc powder cancer claim is somewhat nebulous. 

A long time ago, talc contained some asbestos. Asbestos is bad because it causes cancer. If talc is highly refined in modern facilities, it *should* contain no asbestos.

There have been a few articles that show a minimal correlation but essentially the numbers simply don't really show much either way.

IIRC, one of the claims is that J&J did not mark their product "For External Use Only". Talc is fine for external use, but you should not inhale, eat, breathe, or insert it. Some people use talc too much, and put it too close to their body openings where it could potentially go inside. It's bad to put anything inside your body that doesn't really belong.

Even if the talc powder used is pure talc and doesn't have any asbestos, it could be an irritant to the special skin inside your body (epithelium). That's because under a microscope, talc is made of very sharp crystals of rock. The jury is still out if this causes cancer or not. That said, it's probably best to avoid it and not put it inside your body.

Talc has been used for such a long time that it is not considered a drug by the US government - it's a cosmetic. Cosmetics do not need to be tested and approved by the FDA the same way that drugs are.

So anyhow, whether you are a lady or a guy or someone in between, you can use talc on your outside parts but don't put it inside you.

Edit 1: Typo correction.