Winter White Hamsters

Question
QUESTION: I am planning to buy pearl winter white hamsters from a breeder. I have checked that they are siblings. I want to breed them but I checked on the Internet and some says it is ok to breed them while some says it causes genetic problems. My question is if I really want to breed siblings, would it be okay and would the baby hamsters all have genetic problems?

ANSWER: Never breed brother and sister
Problems caused are
weak litters
internal problems
limbs missing
death of litter at birth or abortion during the gestation period
Problems giving birth causing both mum and pups to die
Future infertile parents
Future parents with problems carrying and giving birth to litters

Speak to the breeder who may have unrelated babies to breed from.

---------- FOLLOW-UP ----------

QUESTION: But if I buy them from a shop, the hamsters could also be siblings. If I buy them from different shops, I am scared that the hamsters would fight to death like my friends'. How can I ensure that both situations do not happen?  

Answer
You said you were buying from a breeder
A pet shop is not classed as a breeder they are a retail outlet
I would personally advise you not to go to a pet shop if you are planning to breed but go straight to a show breeder

Pet shop stock is not necessarily going to be good for breeding and they are not necessarily pure bred stock. I know from being a pet shop supervisor and dealing with incomming stock and breeders.

As for keeping stock together:
You cannot keep boys and girls together if you are breeding.
The boys will kill the pups as will a group of females

Boys are best kept separate as adults if breeding as they will fight
Girls can be kept together until you breed them but must be separated once you start producing litters
You can buy aquarium tanks that you can put a divider down the middle for when you split up the females when mated

The only time you can keep same sex siblings together is if you are not breeding. there is still a chance of sibling rivalry and fights to the death especially with the boys at maturity. The key is to give plenty of space.