You should not let your male cat around your kittens.A young male first or second time father can be great around them,nurturing them and playing with them attentively. But as that cat becomes a seasoned stud other things can happen.Further more this scenerio can change rapidly and unpredictably. I know a cat breeder who has far too many animals and was allowing one of her young studs to wander about the house. One of the female kittens she sold at age 3 months was discovered to be one month pregnant at age 4 months and the vet had to terminate the pregnancy.One of my own studs was out one day when I was cleaning my pen and I came apon him biting his 6 week old daughter on the neck,kneading her sides, and attempting to mount her! So you see, event if your stud is gentle around the kittens it is still unwise to leave him with them.