I have a 3 year old boy and there is a party for one of the girls at his nursery. The nursery only has 8 kids in his area. They do all their activities together and get on well (as well as 3-4 year old do!). All 6 girls have been invited to one of the girls party but neither boys have been invited because apparently "the party is just for girls and will have a girly theme"
AIBU to think that party invites by gender are not the norm for this age and just help to start the whole boys are different thing. I can't put my finger on it but it just doesn't feel right to me.