If we take a look at the World Bank’s global statistics, there is an unbreakable pattern that repeats itself in practically every country in the world: Women live longer than men. Conventional wisdom often dismisses this phenomenon with a quick response based on lifestyle or “men take more risks.” And although there is some truth in this, the scientific reality is much more complex.
Because? To understand female longevity, We must focus on the DNA that we have in all our cells. Something very basic is that women have two X chromosomes, while men have one X chromosome and one Y chromosome. A fundamental difference, because that second X chromosome in women acts as a kind of backup.
This means that if a gene on one X chromosome suffers a mutation or is damaged, the female body can turn to the healthy copy on the other chromosome. Men, however, play a single card, since if their only X chromosome has a defect, there is no plan B. In addition, this chromosome is vital because it houses a large number of genes related to the immune system, which gives women a more robust response to infections.
It goes further. Genetics is not everything here, but the body has an ace up its sleeve, which are the mitochondria, which are nothing more than the “power plants” of our cells. These organelles are inherited only maternally and, as proposed in 2007sexual differentiation has a direct biological cost for men, translating into lower mitochondrial function and, therefore, greater cellular oxidative stress that accelerates aging.
The hormones. Beyond genetics and mitochondria, we must mention sex hormones, which are in very different proportions between sexes. Estrogens, for example, are the main female sex hormones that, in addition to regulating the reproductive cycle, act as a powerful antioxidant shield.
Among its effects stands out maintaining the flexibility of blood vessels, reducing “bad” cholesterol and preventing inflammation. This largely explains why the incidence of cardiovascular disease in women is significantly lower before menopause.
In the man. On the other side of the coin we have testosterone. Although it is crucial for the development of muscle and bone mass, high levels of this hormone in men are historically associated with increased cardiovascular risk at an early age and long-term depression of the immune system.
The evolution. Someone may fall into the idea that this system is something exclusive to humans, but evolutionary biology shows us otherwise. Here, a 2025 study analyzed 1,176 species and the results revealed that in mammals, females live on average 13% longer than males.
The reason lies in reproductive strategies and the biological wear and tear derived from male sexual competition, such as fights over territory or mating. However, it was seen that andIn birds, males live 5% longer; since in the avian world, males usually have two identical sex chromosomes (ZZ) and females have different sex chromosomes (ZW). Furthermore, in many bird species, parental care is shared or falls to the male, which reduces their risk behaviors.
Human behavior. Of course, biology does not operate in a vacuum and genetic and hormonal factors must be added. the behavioral gap and social. For example, the consumption of toxic substances has a greater prevalence in men, being associated with cancer, cirrhosis or respiratory diseases. But, as we have said before, testosterone is also linked to a greater propensity to take risks, which translates into higher mortality rates from traffic accidents or cases of violence.
On the other hand, women suffer from “invulnerability syndrome” which causes them to seek preventive medical services much more frequently. Men tend to postpone visits to the doctor until diseases are in more advanced stages, making treatment difficult. In addition, women tend to build stronger social and emotional support networks, a factor directly linked to greater survival in old age.
Images | Age Cymru
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