How much of our initial conditions come from past Kamma?

When we come into this world, in a rebirth, how much of our situation is predetermined by our past Kamma? I think I have some understanding of the role of inherited Kamma in our personhood. But, are there teachings which indicate if our genetic makeup (good or poor) and our initial social/economic situation (born to rich or poor circumstances) are influenced by it? To ask in another way, does a person with negative Kamma have a likely-hood of being born with worse health and in poorer circumstances than one with positive? Or are these 'random' factors, uninfluenced by Kamma? Or is this an unanswerable question? I sense these are unrelated but I have not found guidance yet in this issue.