nits
men have shorter hair
and may be less inclined to rub up against others so much (affection)
Women have a lot more hair and possibly more physical contact including with kids & other people's kids (due to socialised roles)
Anecdotally - when I was a late teen, I got lice, and so did the boys I was friends with including my boyfriend. We were grunge types and the boys all had long hair, my boyfriend had waist length hair
I've also heard that mosquitos bite women more - due to our skin being "less tough" and our blood being "sweeter" - how much of this is cobblers I have no idea.
We could be more sensitive to bites, react more? We have a keener sense of smell, do we feel itches more?
With lice, do we feel more disgust? Is it harder to get rid of? Many men would just cut their hair dead short wouldn't they, it's probably more difficult for us to manage.
Dunno.
Why do men take 15 hours to take a shit? That's an as yet unresolved sex difference. I suggested to DH it was because he had "poorly developed, weak internal muscles" just to switch it up from always being women who are framed as weak, the exception. He conceded this may be true based on the whole pushing a baby out capability thing.