Readers and friends who grew up watching Journey to the West remember the "daughter country" where everyone from the king to the common people were women and there were no men?
Now I want to tell you that in the future, the daughter country may really exist.
Shorter and shorter Y chromosomes and fewer sperm
After experiencing a series of studies such as baldness and thermos cup of goji berries, the male compatriots have come to the heart again: scientists have found that the male crisis is coming, the Y chromosome is disappearing, it is speculated that the Y chromosome will completely disappear after 5 million years, and the future male will become extinct!
Biology teachers have taught that in the long history of mankind, the protagonists who determine the sex of men and women are the chromosome family: X and Y chromosomes are formed millions of years ago, and the Y chromosome is very critical to the survival of male compatriots, and the lack of these genes or functional abnormalities will lead to disease and even inability to survive.
Jennifer Grave, a prominent geneticist at the Australian National University, warns that male genes are receding and slowly disappearing, and that men are on the road to extinction.
"3 million years ago, the Y chromosome had about 1400 genes, but now there are only 45 genes left, so the Y chromosome will lose all of its genes in about 5 million years."
The Y chromosome is degenerating, the question is what will be the consequences? The male Y chromosome has genes responsible for developing into the testicles, which secrete male hormones, which are important components that characterize masculinity. Once the Y chromosome disappears, the male may disappear.
In fact, in the past 50 years, the biggest debate about men's reproductive health has been the decline in the quality of male semen on a global scale.
The Institute of Science and Technology of the National Population and Family Planning Commission of China has studied the sperm analysis data published from 1981 to 1996, from 39 cities and counties such as Beijing, Shanghai, Tianjin and other 256 literature, a total of 11,726 people, and found that the semen quality of men in China is declining at a rate of 1% per year, and the number of sperm has dropped by more than 40%. Moreover, the more industrialized the region, the faster the decline in sperm quality.
Xiong Chengliang, former director of the Institute of Family Planning of Tongji Medical College of Huazhong University of Science and Technology, pointed out at a conference in 2018 that the downward trend of male semen quality is becoming more and more serious, especially after the release of the second child, the fertility of older men after the age of 30 is worrying.
According to the systematic statistics of semen parameters in elderly men, the sperm parameters of elderly men decreased year by year, including sperm concentration, sperm quality, sperm motility and the number of sperm in normal form, and the decline rate was 0.3%, 0.4%, 0.6% and 0.7% respectively.
What does this set of data illustrate? Xiong Chengliang analyzed that at this rate, one day Chinese men and even men around the world may all suffer from azoospermia.
On the other side of the world, a survey report from the Hebrew University of Jerusalem also confirmed Xiong Chengliang's conjecture that male sperm counts have decreased by 59.3% and sperm concentrations by 52.4% in the past 40 years.
Survey report of the Hebrew University of Jerusalem
According to historical data from the International Health Organization (WHO), in 1940 the lower reference value for normal sperm count was 113 x 106/mL, in 1990 the lower reference value for normal sperm count fell to 60×106/mL, and in 2010, the World Health Organization again lowered the reference value for lower sperm concentrations from 20 x 106/mL to 15 x 106/mL. The declining value directly reflects the general decline in male reproductive capacity.
In fact, since 1992, when the first study reported the decline in human sperm quality, there has never been much good news from the medical community, but there have always been voices of doubt, such as samples from infertile men who sought medical treatment and were therefore not convincing, or different ages and abstinence situations distorted the data.
But the ever-coming research data is yet another reminder that we may no longer be able to delude ourselves into ignoring the problem.
How will humanity reproduce now and in the future?
Men who are "spermless" are not necessarily unable to have children
For many men today, the problem of azoospermia has long passed the reproductive age, but in order to avoid tragedy, the medical community is also racking its brains to find various countermeasures.
There are many causes of azoospermia, which can be summarized into obstructive azoospermia and non-obstructive azoospermia, and the treatment strategies are also different, and they are not 100% treatable.
Patients with obstructive azoospermia have normal spermatogenic function of the testicles themselves, and can open the blocked vas deferens through surgery such as compound surgery, so as to achieve normal fertility.
Patients with non-obstructive azoospermia who have dysfunction of the testicles themselves can search for sperm in semen or reproductive organs through endocrine therapy or surgery, and then use assisted reproductive technology to achieve fertility purposes. For various reasons, the success rate of finding sperm is also different, and the overall rate is between 40% and 65%.
However, the use of assisted reproductive technology is expensive, the risk is not small, and men's self-prevention is far safer and more reliable than relying on medical means.
What should I do if the Y chromosome is gone?
For mammals, the disappearance of the Y chromosome means the extinction of individual males and even entire species. Are there any cases where the Y chromosome disappears and the species continues to survive?
The mole-shaped vole and the two Japanese spiny rats are typical examples. In the process of evolution, the Y chromosome was inadvertently lost, and the gene that determined others disappeared, but the gene CBX2 of the second chromosome of this species played a role in determining male sex. This news may give humanity a renewed confidence.
But some scientists believe that even if the Y chromosome disappears, another human chromosome will take on the work of the lost Y chromosome, which will lead to the birth of a new human race.
There is also the view that humans will most likely continue to need males for normal human reproduction.
Can two eggs also produce offspring?
As early as 2016, Li Jinsong, a researcher at the Shanghai Institute of Biochemistry and Cell Research, published the research results in the scientific journal Cell Rsearch: by modifying the genes of oviparous embryonic stem cells to make them have sperm function, these cells were then injected into eggs, creating healthy young mice with a pair of eggs.
Little female rat without "Daddy"
At first, researchers were only interested in the genetic similarities between eggs and sperm-producing stem cells. But out of curiosity, they injected an oviparous stem cell into a mature egg, and actually produced an embryo. The researchers used the same method to experiment with the genetic material of two fathers but it did not work.
Although this research is another breakthrough in the field of haploid cell line research, Li Jinsong himself is still strongly opposed to the use of this technology to create human offspring, and there are still many ethical problems along this road.
For a long time, in the people's concept, once the child is not conceived, it is often the responsibility of the woman, but more and more evidence shows that less than half of the fertility problems are related to women, and the other half are more than men.
Today is the World Men's Health Day, here to remind men of childbearing age, many times as long as a little change, such as releasing stress, eating more vegetables and fruits, eating less meat, quit smoking and alcohol, more rest, may be able to solve the above problems.
In addition, although the conclusion that men are going to go extinct is scary enough, in the next 5 million years, we may still face more pressing problems such as virus invasion, global warming, food crisis, etc., and we don't have to worry too much