Would You Trade Fertility For A Longer Life?

By Joelle Renstrom | 7 years ago

FertilityLast year, Google announced the formation of Calico, a new company aimed not just at healthcare, but at tackling the “challenge of aging.” In other words, Google wants to “solve death,” and joins futurists and scientists such as Ray Kurzweil and Aubrey de Grey in the fight against senescence, the decay of our bodies that generally comes with aging. De Grey has identified seven types of aging damage, many of which involve cellular atrophy and mutations, that help direct researchers toward cures. Kurzweil has his own supplement company designed to help slow down aging. Increasingly, scientists are working on life extension, but new studies show that reduced fertility may be the price (or one of them, anyway) for achieving it.

Back in 1979, a gerontologist proposed that “it may be selectively advantageous for higher organisms to adopt an energy saving strategy of reduced accuracy in somatic cells to accelerate development and reproduction, but the consequence will be eventual deterioration and death.” In other words, if organisms reserve energy to promote a longer, healthier life, they’ll be less likely to reproduce; similarly, if organisms devote more energy toward reproduction, they will hasten their own decay and death.

In the past few decades, scientists have been able to identify a hormone directly involved with aging, called IGF-1. They first pinpointed the hormone when studying a worm that reacts to environmental stress by reducing its IGF-1 levels, which puts them in a kind of stasis that keeps them alive but unable to reproduce. Scientists believe that all mammals experience something similar, and that the IGF-1 hormone controls the body’s use of energy.

If IGF-1 levels are low, the body concentrates on survival, directing energy toward repairing cells and DNA and away from reproductive processes. Low levels of IGF-1 may decrease a person’s chances of contracting Alzheimer’s or dementia, as scientists have found a correlation between getting such diseases and high levels of IGF-1.

Studies with mice suggest it might be possible to control the levels of IGF-1 in our bodies through diet and other methods, though it’s more difficult to test this hypothesis in humans given our already lengthy lifespans. So while this all sounds well and good, lowering IGF-1 levels may have a significant effect on reproduction, especially for women. A study published a few years ago indicates that fruit flies altered to stop producing IGF-1 lived a lot longer than normal, but couldn’t reproduce at all.

While scientists continue to investigate the mechanisms and reactions set in motion by tinkering with IGF-1, it’s likely that the hypothesis first set forward in the late 1970s will hold true — perhaps even more than scientists anticipated. I have to wonder whether this is some kind of biological response to the threat of over-population; perhaps in the long run it’s better that lifespan and fertility have an inverse relationship. I don’t think we’ll reach a Children of Men scenario any time soon, but we may see what humankind is willing to trade to avoid or delay death.

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