Breeding from the same sire

Question
I have two Himalayan cats from different litters but they are from the same sire. Is it ok to breed them?

Answer
Jeannie
They are effectively half brother and sister
Personally I would not recommend this mating unless the breed was suffering from inbreeding depression or is numerically small across the whole breed. My suggestion would be to offer the male as a stud to others and mate the female out.