QC

100% serious question: why do nerds have such different voices from jocks?

men who exercise a lot as teens produce more testosterone & change the size of their vocal cords?

It's an interesting question. Without thinking too much about it, it could just as easily be a selection effect: men with more testosterone are more likely to become jocks. I don't claim that this is definitely the case, but seems plausible at least.

Yeah, I used to think testosterone explained almost the entire thing, but now I think there's also another effect where nerds breathe higher in their bodies than jocks (possibly because they exercise less, or have asthma, or something) which makes their voices higher / thinner.

Oh, and another possibly stronger effect is tension in the chest. When my chest is properly relaxed my voice gets a *lot* more resonant. It's awesome. Strongly suspect nerds have more tense chests than jocks.