I have a colleague who's driving me crackers right now. She has a son and we both work with young children (I have no DCs). She makes constant gendered comments about boys and girls, both her own son and the children we work with.
Example: 'I was surprised he was able to do that, I mean girls would be fine with it, but not boys'
'He (her son) eats like a horse - typical boy, girls eat like birds at that age'
'He's a boy, he doesn't understand that sort of thing (girl's feelings)' 
At work, she talks about 'boys' toys' and 'girls' toys' and I have challenged her on this in a lighthearted way but it's just driving me mad! I am very anti-gender stereotyping and I don't understand why some people seem so very invested in it.
I guess I just want to do a bit of offloading but would be interested to hear other people's thoughts and/or similar experiences