Hi im really confused about the whole registered breeding thing.I just looked on a breeders website,on this forum and they are breeding registered cats,a particular breed,but they are also crossing this breed with a different one????

both parents(of different breed)are registered,but kittens i presume cant be as mixed breed?Is this an acceptable thing?or can they somehow be registered,There is so much to look into,and i have had a few brain cells die on me since the kids,any advice/info on this appreciated.