Due to an increased availability of basic needs, as well as the great medical advances, the average human lifespan has increased significantly. The average lifespan of humans varies among different populations, still, wit a few exceptions, women seem to live longer than men. In the US, the average for women is 80.1 years, while for men it's only 74.8 years. How is a person's lifespan correlated to gender?
There are many factors determining a person's lifespan, and unfortunately, they can not be easily controlled in an experiment. An answer can be linked to social roles. In most societies, men are more likely to fight in wars, work in physically risky jobs, and be more aggressive, which can lead to death in conflicts. However, this explanation consists only part of the answer, but can not account for all the difference. If we consider all the physiological differences based on gender, part of the explanation may be biological. Various studies of animals have shown that females have a greater average lifespan among elephants, mice, and even fruit flies. Still, there is no evidence for any explanation to determine the reason for this longevity difference, nor how they are related to humans.
One difference however is obvious. Sex hormones play a large role in the differences between male and female. For example, estrogen helps eliminate cholesterol, while testosterone increases the levels of low-density lipoproteins (the "bad cholesterol"). Again, this could account for another part of the difference in mortality: heart disease. Also, women generally have slower metabolisms than men, and many studies of animals have related slower metabolism with longer lifespan.
Another major difference between men and women is genetic. Females have two X chromosomes, while men have one X and one Y chromosome. A number of diseases, such as hemophilia, are much more common among men because a gene on th second X chromosome blocks the defective gene that causes the disease. Moreover, the X chromosome also includes a gene that is used in the repair of DNA. Because men have only one X chromosome, if it's defective he may experience more of the effects of aging and disease, as unreported mutations accumulate in time.
However, all explanations address the average lifespan of humans, but it does not set a rule. Not all women live longer than men, and a person's chances to live a long life can be significantly increased by a healthy lifestyle. Maybe nature (or genetics) has favored women, but one's lifestyle is certainly linked to the lifespan.