[b][b]Stereotypical/Sexist[/b][/b]
Both of these meanings wont be as serious by being racist but it's still not a good thing to do. Being hatred against another gender or just bulling a kid cause he hasn't got much of a manly voice is still also rather harsh. I would talk to them about their actions and hope they understand what they have impacted on other people. If they due to carry on I would give them a verbal warning so they get that we do take it seriously and it should not be tolerated. This would normally be as far as I go. But after insults and sexists messages I would gag/mute them and possibly slay them.