To find out what was going on, Pimenoff used the genetic diversity among type A today to calculate that it first emerged roughly 60,000 to 120,000 years ago. This makes it much younger than the other kinds of HPV-16 – and crucially, this happens to be around the time that early modern humans emerged from Africa, and came into contact with Neanderthals. Though it’s hard to prove definitively, Pimenoff believes they immediately began swapping sexually transmitted diseases – and that the split in the variants of HPV-16 reflects that fact that we acquired type A from their antescendants.