Would be interesting to hear from more experienced breeders then, because I have the same thought. Even at that age, it still seems to me as if a lot of changes need to happen?

I dont know how people can tell from birth - as in my last litter one of my girls had a slight tail fault and that wasnt obvious until around 6 weeks old, also I would think the pattern is also not very obvious ie regarding barring. My little girl at the moment that Im keeping was born looking fully striped It wasnt til about a week old I could see she was actually rosetted and her pattern since has been slowly breaking up.

I dont agree with very young kittens being offered for breeding. Im sure FCS (flat chest) also take a while to show up ie not immediately obvious, and then there is the health check - any heart murmurs? etc

Agree with everything you said lacemoat, but what I am very curious about is how the type of a kitten is detemined before 12 weeks? At what age do you expect to have a good idea what the kitten's profile for example would be like as an adult?