personally, i don't understand what the issue is.....if his mother smokes while the gf is in her house, she is unlikely to explode (the gf), it won't harm the baby, and it's her house! if they feel that strongly, the should refrain from visiting, or as it has been suggested before, meet up elsewhere where she cannot smoke (i.e. pub/restaurant) - but they won't because it sounds like the gf is probably calling the shots here. all they have done is create a situation and the gf is dictating between the son and mother - never a good place to be. i would tell someone to feck off if they told me what i can or cannot do in my house - a *** cheek! now if the mum was looking after the child, or they were staying with her for an extended period, i would perhaps understand. as it is, it's really, really silly and has only caused problems (but then the gf would know that, wouldn't she.....and is probably grinning from ear to ear as a result).