Sex and scientific philosophy: why women live longer than men
It is a recognized fact that women live longer than men. The reasons are multiple. Here an attempt is made to briefly describe some of the factors identified in published studies and to suggest new directions for future research.
It is believed that these studies may lead to the discovery of new factors that explain the discrepancy in life expectancy between women and men. One of them is the area of fetal microchimerism, which is the persistence of a certain number of fetal cells in the mother after pregnancy. Another can be found in additional studies on the system involved in enhancing the mother’s immune system, during and after pregnancy.
Later studies may find that women who give birth live longer than those who do not give birth. Additionally, women who live to be over 100 years old may have special genes that slow down the aging process and reduce the likelihood of heart disease, stroke, cancer, and Alzheimer’s disease.
The X chromosome may be another influencing factor in a woman’s life expectancy. Because women have two X chromosomes, if there is an abnormality in one of them, the normal one can be used instead of the defective one. In this case, the woman becomes a carrier of the disease but not a victim.
Serious studies point to menopause as a determinant of life expectancy. Very few species menstruate apart from women and certain whales.
The evolutionary force required to pass on genes and the need to stay alive and have the maximum number of children may be some of the natural forces that allow women to live longer than men.
In the United States and other developed countries, the average life expectancy is about 80 years for women and about 70 years for men. In Sweden, however, during the eighteenth century it was about thirty-seven years for women and thirty-four for men.
Women are more than four times more likely to outlive men than men for the first 25 years, mainly due to male testosterone. This factor decreases with age, but the gap still remains in favor of women. Sex hormones are a clear factor to consider; Young males are aggressive, high levels of harmful cholesterol that lead to heart disease or stroke.
However, the female hormone estrogen lowers bad cholesterol and increases “good” cholesterol. Recent studies suggest that estrogen treatment after menopause may reduce the risk of death, especially from heart disease or stroke.
Women have longer lasting hearts and better blood vessels, possibly due to the hormone estrogen. Even diseases like heart disease, stroke, cancer, and diabetes end up killing more men than women.
The advantage that women have over men does not apply, however, to women who smoke, drink, are overweight or are subjected to excessive stress, typical of women working in domains previously dominated by men. In reality, there is no gap between male and female smokers.
However, there are some countries where there is almost no such gap, such as India and Pakistan, where sexual discrimination and practices such as female infanticide and bride burning abound.
Mortality rates can also be affected by chromosomal differences between men and women. They both carry genetic mutations that can cause certain life-threatening diseases.
Females have two X chromosomes, so if there is an abnormality in one of them, the normal one can be used, making the woman a carrier of the disease only. Males have one X and one Y chromosome, so they cannot use an alternate chromosome if one gene is defective. The longevity differences described above have been observed in most animals.
Another fact is that men are much more likely than women to engage in violent and risky behavior, which increases the male mortality rate. More men than women also die in car accidents, homicides, and even suicides.
Fetal microchimerism is the persistence of a certain number of fetal cells in a mother after pregnancy. Several recent studies suggest that it may be the cause of some autoimmune diseases. However, the long-term persistence of fetal cells in healthy women is a contraindication. Long-term persistence of fetal cells may also play a role in the development of fetal tolerance.
If the microchimerism is due to the transfer of cells between the mother and the fetus, further studies could indicate the effect of those fetal cells in enhancing the mother’s immune system during and after pregnancy. We know that during pregnancy cells can migrate between mother and fetus in both directions.
As the pregnancy progresses, the rate of cell transfer from the fetus to the mother increases. In most cases, fetal cells are compatible with the mother’s immune system, so the mother’s body does not reject them.
These women, especially those who live for more than 90 to 100 years, are believed to have special genes that slow down aging and reduce the likelihood of heart attack, stroke, cancer, or Alzheimer’s disease.
Other studies may show that women who give birth will live longer than those who do not. It could also be that those who give birth to at least one male live even longer.
The detection of Y chromosomes or male DNA in women after pregnancy, even in a woman who had her last child many years before the blood sample, can support this theory.
In general, stem cells can replicate and are capable of self-renewal in the long term. Since they do not have specific structures, they can evolve into specialized cells such as heart muscle, nerves, or blood cells.
The sources of blood stem cell transplants are the bone marrow, peripheral blood, and umbilical cord of newborns. A new technology that has generated new business is the collection of baby umbilical cord blood stem cells, which are stored for future use.
The advantages of stem cells from the umbilical cord along with the fact that there is a transfer of cells between the mother and the fetus may be another factor that explains and supports the theory that women who give birth will live longer than those who give birth. They do not do it.
Finally, it should be emphasized that the reason women live longer is based on many factors, just a few of those mentioned above.
The Bible says (Genesis 16): To the woman he said: I will greatly multiply your pain and your conception; with pain you will give birth kids; and your desire will be for your husband, and he will rule over you … ‘.
The Hebrew version has: ‘… with pain you will give birth Kids‘.
Although some may claim that ‘Boys’ or Banim is the generic name for boys, one may wonder if the original was really ‘Boys’ …
The longer life expectancy of females could be part of some grand Darwinian scheme whereby mother nature rewards motherhood, and especially women who give birth to at least one boy; mothers can earn another five years of life for their effort … and they deserve it …