One of the reasons that mother's longevity is positively affected by births, beyond the massive dousing of progesterone, is that the fetus is used as a type of chelating repository to dispatch with a certain amount of toxic burden, esp heavy metals.
Babies inherit them from mama. I suspect aluminum, but we'll find out in a year when we do more testing. Many times what is thought of as a food allergy is actually the baby reacting to trace amounts of heavy metals in food because they already have a heavy metal burden they're trying to detox.
Other possibility was mycotoxins (mold) or hidden toxins in food and the environment.