Human evolutionary pressures

For some reason I thought about how the fashions of human matchmaking can shape the future of the human race – specifically our height.

In the western cultural sphere it's generally considered a bit strange to have a couple where the man is shorter than the woman. If this persists, it could make the human race a funny one where the females are considerably smaller than the males.

In short (hah!), a short woman will have all of mankind to choose from and a tall man will have all of womankind to choose from, unless they want to face constant weird looks from people they meet on the street. A tall woman will only be able to choose a mate from the tallest subset of men, and vice versa.

It'd be interesting to see if there's historical data available on the average height for men and women, and if it's possible to find out when the "man must be taller" thing started. Is the same fashion active in other cultures too? If not, it'd be neat to see comparisons of average heights for the various cultures.

Now you might think that I'd spend two minutes looking up the answers on the Net, but then I might find out that I'm all wrong – and where's the fun in that?