Like fakeboobs says,
Studies have been done, but not in as broad a range as most other legal drugs.
But in my experience, Me and my 3 brothers were all born to a pothead mom. We have all done very well in school and 3 of us have genius IQ's. one of us is SSI(bi-polar). My wife smoked through both of her pregnancies and our two kids have been discribed as some of the smartest kids people have run into. Take what you want from that info. Fact is, There's no definitive way to determine if any side affect exist.
The only common thread I have seen with all pot babies I've met was a high metabolism.