Well rosie is definatly a girl but still not sure about sally. She is still only little when you press on her nothing really pops out but still not sure. Not seen any sign of them mating or anything will just have to wait and see when she gets a bit bigger. If not looks like i will be buying another cage as kids have already decided if there has been a mistake we will be keeping the babies so could end up with alot of guinea pigs. Or i could rehome them to my brother and sister in law as they both love guinea pigs