Basically, DH thinks it's fine to say farty-farty whenever DD has wind, which she thinks is hilarious and now copies.
I've said that I don't think it's a nice word for a child to learn. My argument is that fart is along the same lines as 'crap', not offensive as an adult but you wouldn't want your toddler saying it. He says it's not the same at all and that fart is utterly non-offensive. It's not a huge deal, we're kind of just a bit bemused with each other's views over it. So who is being unreasonable?