the ONLY safe & SURE way to determine the sex of your Ball Python is to take them to a vet & have them probed. There are some places where you can find info on how to do it yourself but if you make even a slight mistake, you can do serious damage. There is also a way to get a good idea by looking at the tail, but that is not sure fire either. When my vet looked at my BP's tail, he thought for sure it was a male. Once he probed tho, he realized it was indeed a female! Good luck & welcome to the greatest snake forum in the world!!