Only if one posits human creation by a Creator that transcends genes and environment who implanted the ability to transcend genes and environment can humans have free will.One of the more frustrating aspects of this particular claim is that one seems to find quite a few atheists who would agree with it. It is a depressing fact that determinism appears to be a far too prevalent opinion among many scientifically oriented people. But we cannot go by the popularity or unpopularity of a point of view. Is Prager correct to say that without God there's no free will? No. In fact both Prager and the materialists who deny free will are wrong. The fact of free will is axiomatic and it is not in fact possible to rationally deny it. Those who attempt to deny it are implicitly relying on their ability to choose their own views by their own free choice -- otherwise they would be determined to believe in determinism and would have no choice in the matter. They are saying in effect: I freely choose to believe in the fact that we are all determined -- an obvious contradiction. Thus, contrary to what Prager suggests our genes and environment do not determine our thoughts and actions. Determinism is false, even in a world without God.
Furthermore, notwithstanding much rhetoric to the contrary, an omniscient God, far from supporting the idea that man has free will, substantially undermines it. This follows from the fact that if God exists and knows all, including all future events and choices then those choices cannot really be considered free. Some variants of Christianity go so far as to support the doctrine of predestination which is arguably itself a form of determinism. No, I'm quite sure that free will is in fact much safer without God.
I'll try to address Prager's remaining points in my next post.
Update 8/24/2008: Added link to Part III.