I've read Melanie dreher's study on cannabis and pregnancy. Her studies followed a few control parents whose mothers didn't smoke it during pregnancy and some that did. It was done in Jamaica and followed the children's lives until the age of 4 or 5. The children of the mothers that did smoke weed during their pregnancy resulted in children that were more sociable and intelligent than those who hadn't. I believe that also hit there milestones quicker. I found this study quite interesting and good advice. I can't remember if the children were breastfed while their mothers smoked it, too, but I would assume so.

I just figured I'd put that in with this discussion after I read genetic's post.