Well I don't know, but the most likely answer is "being dead". The only thing that'd really have any impact on culling the gene pool is a huge cataclysmic event, which would be more likely to wipe us all out. Remember that on the evolutionary tree there are a hell of a lot more dead animals than live ones.
Actually, a slight immunity to some huge, deadly, contagious disease. Obviously some of us may have it already but then when the event happens only those with the resistence will survive. How dull, I wish it were wings.
Actually, a slight immunity to some huge, deadly, contagious disease. Obviously some of us may have it already but then when the event happens only those with the resistence will survive. How dull, I wish it were wings.