Earlier quoted context omitted.
Even a small differential in reproductive rates would lead to a rapid increase in the prevalence of the trait. Just look at the example of blue eyes -- 15000 years ago nobody had them and now nearly 7% if the world's population do.
Do people with blue eyes reproduce more? I've not heard that before. I thought the ratio of blue to not blue eyes was due to the whole dominant/recessive gene thing (do I mean gene, or maybe allele? a long time since I learned this stuff at school).
http://www.independent.co.uk/news/science/how-one-ancestor-h...