there are 2 sexes but a lot of genders. when a child is born, you have to take care of them as the sex they are because they are uncapable of understanding the difference between all the gender identities. it’s not trans*phobic or cissexist it’s literally giving the child proper care
ummmmm… alternately you could just treat them neutrally until they discover for themselves what they want to be. i’m really fucking glad my parents did that instead of forcing super girly things on me all the time because i’m certain i would have hated that.