The Most Mysterious Cells in Our Bodies Don't Belong to Us

It is well understood that women have cells from their children for at least a decade (probably more) after pregnancy. My wife progressed to pneumonia or severe bronchitis every time she got a cold until after our first son came along. Now, almost a decade after our last child's birth, she has no lung or bronchial problems.

My wife developed motion sickness during her third pregnancy that she still has, although with diminishing severity. Our third child (a son) is autistic and had severe balance issues for several years. The coincidental timing is suspicious.