Half of every litter has the create-a-pet body type

[Cats]

So I haven't seen a lot of talk about this even though it seems to be an 'issue' in other peoples games as well where half of every dog/cat litter comes out with the create-a-pet body type, I'm currently in the middle of testing to see if it can be bred out but I thought I should stop and see if anyone knew what causes this or if there's a way to fix it?