While I do not in any way advocate close line breeding (brother to sister, father to daughter, mother to son etc. and by the way, in cats, it is not accurately referred to as incest, it is called Close Line-Breeding) what it DOES do is enhance the possibility of any less-than-desirable genetic traits that both the male and female may be carrying and pass them right along to the offspring. But on the other hand, it also enhances the possibility of desirable traits to be passed as well.Originally Posted by kittymeow
I also want to tell you that if you cat is pregnant by its brother, that is not a good thing....your kittens may have genetic problems because of this. I know that my humane society wont even adopt out kittens born of incest because of its liabilities!!
In a first time breeding of littermates, the genetic probability of deformity or other physical defect is really quite small. It is when you continue to breed that line back to that line closely that you begin to see abnormalities in the offspring.
I don't think there is a need to alarm jelani by saying her cat's kittens may have genetic problems when the chances of that happening from a one-time "oops" breeding are relatively low.