its not worth risking your credibility as a parent. there are things that can happen to you as a parent and I think its important that you consider these things when making decisions like this. The responsibility of parenting doesn't end when our children are not with us. What happens can directly impact your child...
Personally I don't see any problem with it. I've done a ton of research on the matter my entire family smokes pot. As long as my little lady isn't inhaling anything have all the fun in the world.