what do you do if your little boy wants to do "girly" things?

ok so I'm not sure how I feel about it all but I have a 5 year old boy. he hangs out with his older female cousins alot so he picks up alot of their interests and mannerisms. he's been known to tell me he has a boyfriend, he tries to ask for pink toys at the store, he has tried to pretend he's putting on makeup, just little things like that. most things it's easy for me to brush off as a curious child or him not viewing stigmas like an adult would. my husband however takes those things to heart and is scared to death it means he wants to be a girl. as normal as it is now days for people to switch genders, I wonder if that's something you correct or do you let them do those things and call it expression? how do you know if it's because that's what he wants or because that's what he sees?