You might want to lay some of that blame at Donner, Lester, Puzo, Salkind, and the Newmans' feet. It was their story that had a de-powered Superman in bed with Lois.
I suppose a little bit can be tossed back at them, but
they didn't decide it was a good idea to give Superman an illegitimate child because of it. That particular bit of genius can be laid pretty much solely at the feet of Bryan Singer.