Hi, I have 3 girls that we got from the pet store as pets for my son. They had a litter each soon after we got them. I read the sticky of how to sex the pinkies but had one question. I can't really tell a difference in the genitals but am I correct in assuming that if there are no nipples them they would be boys? If so it looks like the entire litter are boys. Is that possible? The litter is one week old today. The other litter is one day old today and I haven't messed with them. From what I can tell she may have 13 pups. Actually I don't know what baby mice are called but pup sounds cute.