A historical study of castrated men in Korea finds that they outlived their peers by a wide margin
“Our study supports the idea that male sex hormones decrease the lifespan of men,” the authors write. Based on earlier research, the authors argue that one explanation for this could be that male sex hormones may negatively influence the immune system and “predispose men to adverse cardiovascular attacks.” They note further that the theory helps explain why females — in many species — live longer than males.
….And there are other reasons that women may outlive men, including for example the presence of estrogen, which may help enhance longevity. Also, as ABC News reports:
Females may have an advantage in longevity because they have a back-up X chromosome, [Dr. L. Stephen Coles, a co-founder of the Los Angeles Gerontology Research Group,] said. A woman’s body is a mixture of cells, half containing an active X chromosome from her mother and the other half from her father, he said. If there is a defect on one X chromosome, half of her cells will be unaffected.