I would separate them out into separate cages with same sex pairs. Put the male kit with his dad and keep the female with her mom. If you put them all back together, the son will try to mate with his mom and the father will try to mate with his daughter. The son and father would also most likely start fighting over the females, not to mention eventually you are just going to end up with even more chins. They won't see each other as family, they'll see each other as potential mates. There is also no guarantee that they will get along.
You can get them spayed/neutered if you find an experienced vet. Neutering is less invasive but it still isn't recommended to keep two males together with females. I prefer not to put them under the stress of surgery unless it is absolutely necessary as they are known to go off their feed and there is always a risk with putting them under anesthesia.