Here's why:
* Mating: Male guinea pigs can become sexually mature as early as 4 weeks old, and they are capable of impregnating females. Even if the dad has been separated, there's a risk of accidental breeding if they are introduced too early.
* Aggression: Male guinea pigs can sometimes become aggressive toward their offspring, especially if they are still young and vulnerable. It's best to wait until the babies are more mature and can defend themselves if necessary.
* Socialization: By the time they are 8 weeks old, the babies will have had enough time to develop their own social skills and will be better equipped to interact with their dad.
Important Note: It's always best to consult with a veterinarian or experienced guinea pig breeder for specific guidance on introducing a male and female guinea pig, especially if the male is the father of the young. They can advise you on the best approach to ensure the safety and well-being of all involved.