Did you and your wife end up having a baby? My sister is worried about the same thing - except she was born with 3 fused vertebrae. The doctor said she could have children, but it would be difficult.
I agree with adgal. I would think if she did become pregnant the extra weight from the baby would be a concern in the 2-3 trimester...ulitimately leading to limited mobility, and then the concern of delivery. Most women that have absolutely no back conditions experience some sort of back pain or discomfort during their pregnancy or through delivery. I would think (and I'm no doctor myself) that her pain or discomfort level could be more exaggerated. Talk with your doctor. Best wishes!
Well, I am no Dr. but I would think it would require bed rest once she is into 2nd or 3rd trimester. I would definately be talking to your OB ahead of attempting pregnancy. I wish you well.