I''ve had little boys saying how rubbish girls are when I'm around. One time, when I challenged them with "your mum is a girl" (nicely - he was only about 7!) he got really confused. It came from a program on the telly with male and female characters and
he had said he knew everything about all of them, turned out he only meant the male ones.
I've also heard stories from my kids at school - just minor stuff around taking up all the space in the playground, dominating the classroom with mucking around / being noisy, that sort of stuff.
I mean there is - at a general overall level - an issue isn't there. I think it is quite well known so would be surprised if anyone disputed it.
Then when older you get stuff like the girl guides report here
So I think it is difficult when it's personal, obviously we all think our own kids are fab - and the probably are ! - but, looking at society and all the stuff around harassment and all the stuff that most of us will have experienced - these men are all coming from somewhere, they are all someone's son.
Looking at the way things are different in different countries in terms of levels of harassment etc, it is clear that societal and probably family values make a difference, otherwise there would be no difference in prevalence in different countries.
I'm not going to comment about what individuals can do - I don't think that's the right approach as it understandably upsets/annoys people and if they are listening they're probably doing it already.
For me changes in society across the board in attitudes to women, what they are "for", how they can be treated, etc is the way forward which is your basic fundamental feminism IMO so we are all good 