Good question.
That seems to be the case in my families also. One family is crazy about dancing (praised them a lot for doing it) and all members seem to join in, even without praising.

With the Beverly Hills Family, it takes some extra effort to make the hubby do other things than the mum. But I just keep scolding him for doing housework, and praise her for doing it.
And vice versa, when I see mum doing 'man-stuff'. As far as I can tell, it has effect.
I encourage mum to do beauty-things in the bathroom, and she does put on make-up and beauty-masks very regularly. Very funny.
The hubby now rarely goes looking for laundry or do dishes. Instead, he does more of the stuff I reward him for (giving sweet candy/fruit works a lot better.)
They do still try to emancipate, though
So I just keep 'brainwashing' them. Gives me something extra to do, and it's fun for me to run a family in this way, because it's sooooo not my own style!

Oh, and another thing: I didn't buy them the radio yet. All that dancing-stuff doesn't match their life-style in this first generation. They'll get the swimmingpool soon, and got the flatscreen first. But I think the next generation will want to get the radio/MP3 player. I think I'll just not praise them if they go dancing, but not scold them for it either. (Unless they go dance-freaky and I'll need to correct them )