Which is less desirable, to have a boy who acts like a sissy or a girl who acts like a tomboy?

As far back as I can remember, and that is going back a ways, if a girl acted like a tomboy, doing sports, climbing trees, playing in the mud, etc she might raise eyebrows or be rebuked for acting like a tomboy but she faired better in the neighborhood than a boy who acted like a sissy. If a boy wanted to play house, or have tea parties, play with dolls, or do those things that girls did, it was seen as worse. Is it more of a step back for a boy to do traditional girl things than for a girl to do traditional boy thing?