Originally posted by SuperGEM:
Just wanted to mention that the shooting script points out that Jason was born PREMATURE! I think that explains it all, too bad they didn't put it in the movie so everyone could be enlightened right away. 
Now I know I'm a science geek.
I simply *baulked* at this idea.
Right after Lois found out she's pregnant she would have gone for an ultrasound - standard procedure to confirm the pregnancy is not ectopic and to determine foetal age.
They can tell the difference between a two week and a two month old foetus. Even if he had a small birth weight, developmental landmarks couldn't have been that far off and would have been visible on an ultrasound (heart beat at four weeks, nueropore closures, head circumference, weight gain, etc).
It's been mentioned that the kid might not have developed normally, but if he were born and looked human enough I'm assuming he'd have developed at a similar rate. Especially if she got through the pregnancy thinking he were a human child - and how else would she have gotten away without the kid being locked up and studied?
Nope, I'm convinced that she knew it wasn't Richard's. Maybe she didn't know it was Superman's, but she must have known it wasn't Richard's.
/end science geek
