Lots of Questions!!!

Question
First of all, how do you know if a hamster's male or female? Second, can you cross-breed species?(e.g. dwarf hamster with Syrian) Thirdly, when is the oldest age a hamster can be before it absolutely cannot breed anymore? Also, can a very young hamster(about 1-2 months old) breed with a older hamster? What's the limit between the age that they can breed? (sorry, I'm not sure if I'm confusing you =p my friend has a hamster that's about 4 months old, and I'm gonna buy a hamster that might be 1 or 2 months old. I'm not sure if we can breed them.) thanks!

Answer
Male hamsters will have a good sized lump under their tale, and the two holes under the tail will be further apart. Females will have two rows of teets, one on each side of their stomachs. Hamsters should not be bred past 7 months of age, and should not begin breeding until they are at least 4 months old. So if you get a 1-2 month old hamster, it should not be bred yet.

Thanks for writing