It’s an important point to realize that the genetic programming of our lives is not fully deterministic. It is statistical — it is in any animal merely statistical — not deterministic. Even if you are in some sense a determinist — and philosophically speaking many of us may be — that doesn’t mean we have to behave as if we are determinists, because the world is so complicated, and especially human brains are so complicated, that we behave as if we are not deterministic, and we feel as if we are not deterministic — and that’s all that matters. In any case, adding the word “genetic” to deterministic doesn’t make it any more deterministic. If you are a philosophical determinist, then adding the word “gene” doesn’t increase the effect.
– Richard Dawkins (from a PBS interview)