He also wonders if family stress and the stress of the modern world in general may be re-creating in humans what lab rodents experience. “It may be a function of the increasing exposure to stress earlier in life that the population is being exposed to,” he suggests. “I guess, in humans, stress plays a similar function. If you are in an environment that is stressful and dangerous, the chance of having progeny that survive and thrive is lower, so having kids earlier could be adaptive.”
