I have also researched this, from the male's point of view. Most studies and warnings for drugs and pregnancy involve the mother only. While that doesn't mean it can't harm the male or cause birth defects, there just isn't much research out there. My GI told me to go ahead and not worry about it. I had a sperm analysis done, and my count was fine although my morphology was a bit low. But I had it done again and it was OK. My wife's gyno had it checked primarily because she thought the count might be low. I did have more white blood count show up than normal, I guess, but I attribute that to the imuran.
UC diagnosed Dec. 2006
Multivitamin, fish oil, fiber supplement, Nature's Way Primadophilus Optima, Digestive Advantage Crohn's & Colitis