Having lived in a uni dorm and experienced the coming together of kids from single sex and coed schools I’d say that if you want a decent chance of a well adjusted child gender-wise, go coed. If you want hit and miss, go single sex.
Not all single sex kids come out with gender issues, for sure. But in my experience why risk it when nearly all co-ed kids come out with a reasonably well adjusted gender outlook. Or at the very least they know enough to keep any unpleasant views to themselves and not act with the outright misogny you find from some single sex school boys.