[freedumb2003]

IIRC, Asimov(?) wrote a short article -- "Man of Steel Woman of Flesh" or something similar.

It analyzed what would be required for Superman to produce progeny with Lois. The first problem is that his super sperm would blow the top of her head off. So, he would have to do the hand jive and then use his super speed to catch it.

I can't remember the rest -- I'll see if I can find it.

[new cruelty]

Perhaps you are thinking of Larry Niven's Man of Steel, Woman of Kleenex

[Louis Foxwell]

I had somewhat the same setof thoughts. Imagine a Superman erection...
Now imagine superman impregnating 1000 virgins a night for 30 years. If he were truly interested in progeny that would start a new race of Supermen.
Hitler redux.