Epigenetic changes during gestation cause phenotypic changes in the trajectory of development. Environmental toxins and variations in nutrients also change the way the initial software load of DNA plays out.
They gestate in the same womb at the same time in the same amniotic sac with the same placenta.
Try again.
Exactly!
The trajectories for most chronic diseases are established early in life and require misregulation of inflammation for disease onset. That makes it pretty clear where the big pay-off will be in terms of safety information, exposure avoidance, and meaningful prevention of chronic diseases. (Of course it is exactlty where we don’t look now in terms of safety testing of chemicals and drugs. This is despite the combined huge regulatory expense already required of companies and the pretense of regulatory agencies that we have chronic disease-relevant safety data to protect the health of kids).