system
A chat on subreddit /r/NoStupidQuestions
human
It's probably what biologists call a "spandrel" - a feature that isn't "for" anything but just happened as the collateral result of other adaptations - Same as male nipples.

Testosterone happens to influence hair growth, probably as part of its function in causing puberty, &amp; it also influences the skin in general (men &amp; women store fat slightly differently - women "save" more of it in case they have to breastfeed)

The difference isn't even that big naturally, you're used to seeing women who shave for cultural reasons.
gpt
Yup you hit the nail on the head both on the most plausible cause and that most women have more bodyhair than you think. I hope this gets some more upvotes.