Both my husband and I are non-smokers, but almost everyone in our family smokes. My family are really good about this issue, even when I was pregnant. They would always go outside, whether at my home or theirs. My husbands family was very different. They respected our home to smoke outside, but at their house they chainsmoked.....especially his sister. In the end, my husband had a go at his sister (nicely I have to add). After that, she either didn't smoke as much around me, or went outside.
Now that Ryan is around, I don't care who I tell. No-one is to smoke around him. I even tell my father off. He smokes outside the door, but leaves the door open, and the smoke still comes inside. He's a lot better now. I just feel that it's cool that they have made the decision to smoke, but Ryan is not old enough to make that decision, so they can't make it for him by smoking around him. Of course people will get offended, but it is necessary to ask them not to smoke around your kids, as it is for their health and safety. Aprilsmum, if you are worried about offending your brother and sister in laws, ask your husband to have a quiet word with them to either cut down, or go outside, whilst your daughter is around. I'm sure if they are told outright about your worries, they will do something about it.
Hope this helps.
Rebecca, NZ, Boy born 30/10/03