Or pick some player profiles at random, count how many girls vs guys you find (very easy to tell with high accuracy just by looking at the games they play, yes there are exceptions but they're actually quite rare, I promise you can get >90% accuracy after you do a few).
Steam user base is at least 3/4 male by user count, probably even more by play time.
Doesn't Steam have a very long tail? Most played might not be very representative.
Maybe young men are just boring and all play mostly just a few games, while majority of players that are more diverse have their interests spread more evenly across others?
In any case, I don't think "not wanting to make assumptions about people based on little to no information" really counts as "very rigorous standards".