Is the kid really transgender or just going through a phase of wearing a skirt?
At that age I sometimes played dress-up in my grandma's fancy jewellery, maybe a dress and high heels too. Whoopie. Nobody cared. A kid playing.
Maybe people were less restrictive about gender >40 years ago. Seems like an odd thing to say, but I'm seeing restrictions increasing rather than decreasing nowadays and I'm seeing the rigid connection of sex and gender increasing a lot nowadays.