As long as you have differences in breeding rates, you'll have evolution. I suspect one of the great evolutionary forces operating today is birth control. Today, if people really don't want kids, they don't have to have them. It makes sense to me that there are personality differences between people who want kids and those that don't; and also that some of those differences will be due to genetic differences. So what are we selecting out of the population via birth control? It will be interesting to see.