I was somewhat bemused to read yesterday morning that there is a gene for binge drinking. Further inspection suggests that this gene predisposes some people to experience a stronger physiological response than others when drinking alcohol.
Personally, I would say that binge drinking has more to do with sin, freedom and the perennial search for happiness than genetics. Obviously binge drinking can't make us happy, any more than sleeping around can (and there does seem to be a strong correlation between the two). But whether they know God or not, everyone has a hunger for him, a longing for the infinite, and without knowledge of God this leads us to look for happiness in many places where it isn't to be found. Furthermore, I would say that not finding this happiness, not being able to satiate this desire we have (because for so many people they haven't chosen to reject God, it's just that faith has never been suggested to them as an option) we end up trying to fill up our lives with <i>anything</i> that might make us feel something, be it sex, drugs or rock n roll. Of course this self-destructive behaviour leads us into a downward spiral of increasing unhappiness: only in God and his loving Plan can we find happiness. He has made us for Himself and our hearts are restless until they rest in Him, to paraphrase St Augustine.
I am not some sort of neo-luddite who wishes to exclude science and technology from every facet of life. If people have genetic tendencies towards certain behaviours or illnesses then of course identifying that and seeking solutions can be a good thing. But the increasing tendency to identify genes is part of both the "loss of the sense of sin" bemoaned by Pope Pius XII (once we blamed "the system", now we blame our genes) and also constant reduction of the human person to the merely biological. Yes, I have a body, but I am not my body. Neither am I my DNA. And while we continue to place all our hopes on genetics we will never find the answer to those situations which many would agree are a problem.