Not as a rule, but i've found boys to generally be bigger... In my family, us girl (4 of us) were all in the 7lber region. my 2 brother - first one was 9lb 13oz, and my second one was 9lb 8oz. And us girls are still petite, whereas my borther are quite built (my 17yo bro has a 6 pack and i rippled, adn my 14yo brother is just solid, but a good solid!!)

HTH

ETA i spose you'll find out in about 12w hey caro??!!