There are any number of plausible theories as to why women enjoy a longer life expectancy than men. Differing smoking rates, stem cell effectiveness, mitochondrial effectiveness, and the possible effects of hormones on the immune system are all on the list.
Here's another viewpoint - that hormones influence the expression and activity of known longevity genes:
We have shown that the higher levels of estrogens in females protect them against aging, by up-regulating the expression of antioxidant, longevity-related genes such as that of selenium-dependent glutathione peroxidase (GPx) and Mn-superoxide dismutase (Mn-SOD). Both estradiol and genistein (the most abundant phytoestrogen in soy beans) share chemical properties which confer antioxidant features to these compounds.
This antioxidant protection is reflected in the lower peroxide levels found in cells treated with estrogens or phytoestrogens when compared with controls. The challenge for the future is to find molecules that have the beneficial effects of estradiol, but without its feminizing effects. Phytoestrogens or phytoestrogen-related molecules may be good candidates to meet this challenge.
It's never as straightforward as saying that more antioxidants are always a positive thing, of course. It matters greatly where those antioxidants are directed, and how else they affect metabolism. But the present state of biotechnology and biological knowledge is ripe for theorizing - this is a grand era of discovery, barnstorming and experimentation when it comes to the minutae of our biochemistry. It is promising to see so many new papers in aging research leaping directly from "here it is" to "and here is what we could do," even if I might not agree with the importance of the work at hand.
The great curse of aging research in past decades has been the lack of will to manipulate, influence and intervene in aging. With that passivity gone, it's only a matter of time before the best methods of action and progress win out.
Somewhere out there in the world, some few, scattered scientists are working on projects that none of us would recognize, and which will prove vitally important to the future of engineered healthy life extension. Perhaps one of these lines of research will spring directly from the ongoing analysis of metabolism and genetic determinants of human longevity. Perhaps not - I am skeptical on that count. But it always pays to hedge a little against yourself.