Assortative mating, the tendency to choose mates who are similar to oneself, has been speeding up evolution in humans over the last 30,000 years.
"These results suggest that genetic assortative mating may be speeding up evolution in humans." Assortative Mating at Loci Under Recent Natural Selection in Humans
Fascinating new paper: Assortative Mating at Loci Under Recent Natural Selection in Humans By Nishi, Alexander, , &
People prefer partners who are, on average, genetically equivalent to fourth or fifth cousins