When envisioning a gleaming, medically enhanced future in which things like implant technology, super-personalized medicine, and organ regeneration enable humans to radically extend their lifespans, futurists sometimes forget that the human family also tends to change with time. In a world where people rise each day to spit into a bucket and send their bio-readings to a Google Medicine cloud that records and monitors their daily measurements, it would be a mistake to think the identity of the person spitting in the bucket beside yours will never, ever, ever alter.
In fact, you might call this the "Jetson fallacy," in honor of the classic early-’60s cartoon whose writers envisioned a human space colony 100 years into the future (that is, the 2060s). Living as they did in a city endowed with flying-saucer cars, robot housekeepers, and elevated dwellings, the Jetsons nevertheless remained strangely Cleaver-like in roles and composition: a nuclear unit comprising two kids, a dog, a breadwinning husband—George—who went to work at Spacely Space Sprockets, and a homemaking wife, Jane, who sweetly snatched his wallet before zooming to the shopping mall. Creative as they were in imagining the landscape of the future, the writers were oblivious to the tectonic changes—divorce, the sexual revolution, feminism, the entry of women into the workforce—poised to explode the American family.
With that cautionary tale in mind, I'd propose some additions to the compelling "longevity scenarios" that Joel Garreau discussed in Future Tense as a way of sketching out possible outcomes for what human life might be like in an age of 100-plus lifespans. In the four scenarios that Garreau persuasively offers, it is 2030 and a hypothetical couple, John and Ann Grant, parents of two adult children, are entering their 80s. Depending on the rate at which medical science has moved forward—and the ability of public policy to make these technologies available—the Grants A) are not in much better shape than generations before them; B) can expect to live several more decades, but doddering and frail; C) feel healthier and fit than ever, with 60 or 70 more great years ahead of them; or D) find themselves in a wonderfully altered world where their children can plausibly expect something like immortality. In all four scenarios, John and Ann, bless them, remain married.
But we might also consider scenario E, in which John and Ann Grant take a hard look at each other after Sarah and Emily leave home for college and decide that while they’ve had a great run, life is long—very, very, very long—and they’d like to explore other options. They divorce; John marries a woman 20 years younger, ensuring he will have a partner who can look after his well-being, taking him to all his body-part-replacement appointments as he moves toward his first centennial. Ann finds herself living among exponentially more single women, her social life confined to playing online poker with other divorcees and widows, because humanity persists in thinking women should only partner with men their age or older, even as those men have taken younger second or third or fourth wives. In scenario F, our thinking changes and we decide that women, like men, should be able to dip down and date younger partners, so Ann, at 120, takes a well-sculpted 70-year-old boyfriend, but prudently decides to live with rather than marry him.
Whatever pair-bonding opportunities we as a culture allow Ann, we of course will not think it strange if John and his new wife have a child or two to seal their new alliance, meaning Emily and Sarah accrue half siblings who are significantly younger than they are.