Breeding hamsters isn't as easy as you might think it is. For instance you don't want to breed hamsters with bad genes such as diseases in them. Of course, babies happen, and sometimes you get a pregnant mommy even though you didn't plan it!
       The normal gestation period is 16-18 days and normal litter size is 8-12. However, syrians can have anywhere from 6-24! Dwarves have about the same but will have a little fewer babies. When babies (pups, as they're called) are born, they'll have no fur and their eyes will be closed. Within a few days they should begin to get fur and will start eating solid food at 7-9 days. After about 15 days, they'll open their eyes, and their nursing period should last about 20-24 days. After about 4 weeks, you should remove them from the mother and put them in 2 different cages. One for girls, one for boys. It's important that you separate the sexes. Once this time comes, you can give them away, sell them, or whatever you plan to do with them. Note: If you plan to keep the babies, make sure to put them ALL in separate cages after about 6 weeks (unless they're dwarves) so they don't start fighting.
       Hamsters are great mothers and will need little help from you so just make sure they have plenty of food, clean water, and bedding. Leave the babies alone. Otherwise, the mom may resort to cannibalism if she fears her babies are in danger or if they have a human scent.

       If you have a male and female hamster that aren't sick, have no bad genes, and are the same species, this is how to breed them.
       Put the female in the male's cage. Don't put a male in a female's cage. If you do this, the female will get protective of her territory and harm the male. Now, let the male do his thing. He'll sniff her first, then get on top of her. He'll repeat this process for as long as you let him. After about an hour take the female out and put her back in her cage. Within a little while, she should be pregnant!