Bryan Sykes interview

Link (NY Times)

On the Y chromosomes of warlords:

In fact, whenever geneticists look at evolutionary diagrams, they see some frequently occurring Y chromosomes, not closely related to others. These genetic "explosions" are the legacy of a relatively few very successful men who have supplanted the Y chromosomes of their contemporaries, as Genghis Khan did. My guess is that the Y chromosome of every living man has spent at least one generation in the testis of a warlord.

On the "gay gene":

You are referring to research on gay men and their families published in 1993 by Dean H. Hamer and his team, who located on the X chromosome a gene controlling male homosexuality. Though this was subsequently replicated by Hamer, another study along similar lines failed to confirm the association. Since then, no one has tried to take the "gay gene" any further.

On purely genetic grounds, I never liked the idea of a "gay gene" since it is very hard to see how such a gene could have survived and spread among our ancestors since it is bound to have been eliminated if homosexual men had fewer children than their heterosexual contemporaries. Genes that even slightly reduce their chances of getting passed on to the next generation have very short careers.