While I haven't talked about this with DS, one of his friends has divorced parents. Chances are, his best friend might get a "new" parent at some point and have two mummies/daddies. I know it's not the same as a same-sex relationship, but DS is aware people have different family dynamics. Only vaguely, but he's still tiny!

Sadly, I won't be the one doing this talk with DS. Nursery is given a load of govt-approved books, including books about children with two mummies and children with disabilities which introduces difference matters as normal things very early on. (Great in one way, such as destigmatises things, but also I want DS to know that differences can impact people differently and things aren't straight out of a book: it's so hard! Some people try to hide problems and/or who they are and that's not good, but then you have to say "yes, that's cool, but don't shout about it because it's not cool" or something like that... my word I do make problems for myself sometimes!)

Anyway, DS has three grandmas so why would two mummies be odd?

eta - we live very near the UK's gay capital so DS has seen men holding hands and stuff like that - he just accepts it. We've not gone into the parenting side of it, but we have seen two men in the local playground with one child between them and not even a comment from DS, who is usually very vocal about things he finds odd or wants to know "why" about.