Normally hamsters are separated at 6 weeks old. If they are fighting and ar under that age I would speak to your local vet or pet shop.
Leave the babies alone. Hamsters are known for cannibalizing their babies if they are handled before they are starting to wean.
You should never separate the babies from the mother, you can get your scent on them and she might eat them.
They should be separated from their mother and brothers and sisters at about 8 weeks. Or else they will have babies, or they will fight.
Males should not be with females during pregnancy or birth. It cant be with the babies until they are big. The male will eat the babies. You have to separate them after they mate
Around 2 - 3 weeks, when they are becoming independent and their mother is no longer feeding them
They might cause a fight, if same gender, If not the same gender, the they will (most likely) have babies, and when a female hamster has babies, you have to help the babies come out. And if you touch the hamster babies AT ALL, the mother will eat them. I don't recommend buying another hamster.
No, you should separate them.
kill them
You can leave them in the same cage ONLY if they are dwarf hamsters. No other breed of hamster can you put the male and female together with the babies, the male will hurt, kill, or even eat the babies. The male dwarf hamster, however, can actually help raise the babies with the female.
mom should not kill or eat but will defend her offspring and also male might kill the young if they are anything like rats you should separate dad from all of them
when a hamster has babies you should sale them because if you keep them there would be more and more hamsters to deal with and then end up with cages full of them so i recammened you to sale them.
nothing should effect the pregnancy of the hamster. the babies will come out and be just fine but don't touch the babies until they have fur or the mother will kill them