Baby groups

I must say I am immensely proud of the life I lead now, very respectable, husband, son and dog, soon to be member of a parent and baby group. I am not sure what goes on at these groups, what is the protocol, what is considered acceptable conversation pieces (probably best not to mention the gorilla, not until week two anyway). Is there a dress code? Are we judged by the pram we choose, the clothing our babies wear, will we envy the “Mary-Ellen” that is picture perfect, cooks brownies and her little Johnny said “mom”.