Duke University researchers have published a study that shows that over the past 250 years, women have been more resilient than men, especially to epidemics and hunger. Man is threatened with extinction because his signature, his Y-chromosome, is degrading and has been losing its genes for millennia.
Strong Woman
Read Also: Stress May Cause Spontaneous Abortions of Male Fetuses According to Study
However, recently the speed of the degradation has increased because many men are wearing too-tight pants and are also exposed to rising temperatures, pollution, and electromagnetic waves.
There’s been an alarming 40% drop in the average male sperm count in the last 20 years, compounded by a drop in quality. Some researchers think it’s just an important problem as global warming.
Numerous reasons
We live surrounded by chemicals. The toxicity of phthalates to germ cells, the precursors of sperm, is no longer in doubt. So is the toxicity of pesticides, which also contribute to sperm degradation.
Diet and lifestyle are suspected of being a direct cause of the degradation and alcohol and tobacco are probably the main causes. Smoking degrades the blood vessels of the male reproductive system. In the penis, this is responsible for changing the quality and duration of an erection. In the testicles, vascular changes can hurt sperm production.
The testicles must be cooled
The heat was also mentioned because sperm production is extremely sensitive to temperature. Sperm must be stored at temperatures between 91,4 to 93,2°F. Depending on the temperature, the bursa is contracted or relaxed to maintain a constant temperature. This is why the testicles are outside the body.
An increase in testicular temperature will slow down or even stop spermatogenesis. Based on this observation, many researchers suspect that the main cause could be the tight clothing that men wear.
Stress is also suspected to have a significant effect on the fertility of men, especially in the Western world.
XX vs XY
But the real explanation lies in the Y chromosome which is passed from father to son and is the main difference between men and women.
Females are born with XX chromosomes and males are born with XY chromosomes. Women get an X chromosome from each parent while men get an X chromosome from their mothers and a Y chromosome from their fathers.
The X chromosome, which is 80 times the size of the Y chromosome, also contains 500 times more genes. The XY is an imperfect combination because in a woman one X can fix the other at any time while in a male, X and Y remain on their own devices in case of needed repair.
In men, it is so far not possible to repair the Y chromosome which is as we speak degenerating, and some predict its elimination in less than 200,000 years. Still, some believe the Y chromosome has 4.6m years left.
In a mouse model, researchers are already able to combine the chromosomes from two eggs to give birth to a female from two mothers. Of course, the offspring in this case is exclusively female. This suggests that in the future females could do without males which would ensure that the species continues to thrive at least in its female form.
How do you save men?
By finding treatments that could stop the degradation or making a completely artificial super Y chromosome to produce a new enhanced breed of males in test tubes. Unless one day we go the hermaphrodite route like what is already happening with some plants, tapeworms, and snails. However, by then we may already be knee-deep in a world where cloning is the norm.
References
Skov, L., The Danish Pan Genome Consortium, & Schierup, M. H. (2017). Analysis of 62 hybrid assembled human Y chromosomes exposes rapid structural changes and high rates of gene conversion. PLoS Genetics, 13(8), e1006834. https://doi.org/10.1371/journal.pgen.1006834
Hughes, J. F., & Page, D. C. (2015). The Biology and Evolution of Mammalian Y Chromosomes. Annual Review of Genetics, 49, 507-527. https://doi.org/10.1146/annurev-genet-112414-055311
The Conversation. (2018, January 17). The Y chromosome is disappearing – so what will happen to men? https://theconversation.com/the-y-chromosome-is-disappearing-so-what-will-happen-to-men-90125
Duke University. (2018, January 9). Women survive crises better than men: Newborn girls are hardier than newborn boys during famines, epidemics. https://today.duke.edu/2018/01/women-survive-crises-better-men
