Increased Longevity Versus Reduced Reproduction in Humans?
Human studies may reveal a correlation between longevity and lower rates of reproduction: "A number of leading theories of aging, namely The Antagonistic Pleiotropy Theory (Williams, 1957), The Disposable Soma Theory (Kirkwood, 1977) and most recently The Reproductive-Cell Cycle Theory (Bowen and Atwood, 2004, 2010) suggest a tradeoff between longevity and reproduction. While there has been an abundance of data linking longevity with reduced fertility in lower life forms, human data have been conflicting. We assessed this tradeoff in a cohort of genetically and socially homogenous Ashkenazi Jewish centenarians (average age ~100 years). As compared with an Ashkenazi cohort without exceptional longevity, our centenarians had fewer children (2.01 vs 2.53, p<0.0001), were older at first childbirth (28.0 vs 25.6, p<0.0001), and at last childbirth (32.4 vs 30.3, p<0.0001). The smaller number of children was observed for male and female centenarians alike. The lower number of children in both genders together with the pattern of delayed reproductive maturity is suggestive of constitutional factors that might enhance human life span at the expense of reduced reproductive ability."
Link: http://www.impactaging.com/papers/v3/n12/full/100415.html
I don't think it's the number of children- methinks it is the age of first childbirth. Fruit fly studies have shown that in a very few generations, fruitfly lifespan can be doubled by delaying the age of mating. (I have no idea how they separate male and female fruit flies...)
I believe this experiment is being run wholesale right now, but accidently. In the U.S., whites live, on average, loger than blacks. Blacks, on average, have their first child well before whites do. Non-college educated whites have shorter lifespans then college educated whites. (Education patterns tend to run in families for generations.) Non-college educated whites breed sooner then college educated whites. Going back in my own family history, where in the 1600's my ancestors were living into their 80's and 90's when such was really unusual, I find that my ancestors, right through to my parents, had their first children in their 20's, not at 18 or before, as was usual for the time.
My wife was 23, me 25, for first child. My eldest child- wife and him 28 for their first. My parents are in their 80's- alive but not really healthy. Both smoked, and drank too much. I don't smoke, and drink moderately. I'm a healthy 56, and expect to make it into the low 100's before I drop dead. Based on family history.
I expect my grandchildren will live even longer.