Neanderthal DNA Exists in Humans, But One Piece Is Mysteriously Missing

[Warpy]

2. Well, it wouldn't, not for long

Breeding between Sapiens and Neandertal was most likely infrequent. And like most cross species breeding we know about today, the males were infertile. Fertile females obviously existed, since we're here. I don't know how many generations it took to produce fertile males desending down the hybrid female line..

The Neandertals were wiped out by the Campanian Ignimbrite Event, they were just in the wrong place at the wrong time. Not enough stragglers were left to produce non sterile males through successive generations.

It probably wasn't all bad for the sterile males, any horny females who wanted their fun without the consequences would have found them extremely attractive.

Before modern human men get too confident, the human Y is most likely on its way out, too, but for another reason.. Here is a good discussion of why it's not going to be a problem: https://geneticsunzipped.com/transcripts/2023/03/23/bye-bye-y