This topic reminded me of the following quote from the movie "Mallrats"...
Brodie: He's an alien, for Christ sake. His Kyrptonian biological makeup is enhanced by earth's yellow sun. If Lois gets a tan the kid could kick right through her stomach. Only someone like Wonder Woman has a strong enough uterus to carry his kid. The only way he could **** regular chicks is with a kryptonite condom. That would kill him!
...That's the "Mallrats" explanation of Lois and Clark's fertility problem... Not like it helps, but it is still pretty funny!
-Wanda :p
