Gregory Cochran
Gregory M. Cochran (born 1953) is an American anthropologist and author who argues that cultural innovation resulted in new and constantly shifting selection pressures for genetic change, thereby accelerating human evolution and divergence between human races. From 2004 to 2015, he was a research associate at the anthropology department at the University of Utah. He is co-author of the book The 10,000 Year Explosion.

Human evolution 
In opposition to what he sees as the conventional wisdom that civilization has been a static environment which imposed stabilizing selection on humans, Cochran, along with like-minded anthropologists such as John D. Hawks, contends that haplotype and other data indicate the selection of genes has been strongest since the advent of farming and civilization.

Ashkenazi Jewish intelligence 

Cochran and co-authors Jason Hardy and Henry Harpending suggest that the high average IQ of Ashkenazi Jews may be attributed to natural selection for intelligence during the Middle Ages and a low rate of genetic inflow. Cochran and his colleagues hypothesize that the occupational profile of the Jewish community in medieval Europe had resulted in selection pressure for mutations that increase intelligence, but can also result in hereditary neurological disorders.

Gay germ hypothesis 

Cochran has claimed that homosexuality can be considered a disease because it generally reduces or eliminates reproductive output, and he has speculated that homosexuality might be caused by infection by an unknown virus. However, he does not suggest that the infectious agent that causes homosexuality is spread by homosexuals. Cochran's hypothesis is based on the argument that homosexuality is unlikely to be genetic because it does not follow simple Mendelian inheritance patterns and because natural selection should have largely eliminated genes that cause homosexuality. Cochran has admitted that there is no positive evidence for the gay germ hypothesis, and according to mainstream biology, sexual orientation likely results from complex interplay of genetic, hormonal, and environmental influences.