The Fertility Crisis Among Western Males

About 4%-10% of European and Asian DNA comes from Neanderthals.But strangely enough none of this DNA is on the Y chromosome which only men have.Meaning Neanderthal men did not pass on their genes!It was black men who mated with Neanderthal women that created the modern hybrid white / non melanated races!

When the first Modern Humans (Sub-Saharan  melanated Africans) came out of Africa around 50,000 years ago Neanderthals populated Europe.The two species started having children but the only infants to survive were female. Neanderthal men couldn't make babies with modern humans but scientists believe about 12 female offspring of African men and Neanderthal women survived to maturity Scientists believe the Neanderthal Y chromosome carried harmful mutations for humans. One of them may have been albinism and as many as 6000 genetic diseases that are still present in many European populations If a human woman were to become pregnant by a Neanderthal her body would have triggered a miscarriage, only fathers can pass Y chromosomes to sons!So human Neanderthal boys would not have survived for long if at all. Culminating in the elimination of the Neanderthal Y chromosome and the extinction of the Neanderthal 30,000 years ago! But part of them is still left in European and Asian DNA and a smaller percent in those who have an ancestor from these populations.

Neanderthal DNA influences the health of immune systems, skin (red or ruddy complexion), and psychiatric traits. Neanderthal genes increase a persons risk for Actinic Keratosis, Skin Cancer,(both related to sun exposure) Also hyper coagulability which causes strokes and embolisms. Some neanderthal dna increases the risk for depression, autism,smoking,drug abuse, alcoholism and suicide.Although the Neanderthals, died off approximately 30000 years ago,  the exact cause is still up for debate.A causality between millennial-scale climate cycles and the replacement of Neanderthals by modern humans in Europe has tentatively been suggested.   Ecologic stress during stadial expansion of steppe landscape caused a diachronous pattern of depopulation of Neanderthals, which facilitated repopulation by melanated modern humans who appear to have been better adapted to the environment. Climate change could pose a threat to male fertility.University of Lincoln evolutionary ecologist Dr Graziella Iossa and behavioural ecologist Dr Paul Eady explain Dr Iossa said: "It is well known that the reason why testes are usually located outside the body cavity in male mammals is because sperm is damaged by excessive heat inside the body. However, it is now becoming clear that when subjected to heat stress, males become infertile before females do."It is not only intriguing that males and females show different sensitivity to temperature stress, it may also tell us something about how species will be affected by climate change and how we might buffer or tackle these sensitivities.""Our study is consistent with current evidence that the production of sperm and mating behaviour are sensitive to developmental temperature and, in an era of global warming, further research in this area -- examining both male and female fertility -- is vital.