I have a genetic disorder and I have given birth to two children, one who has the same disorder and one who does not. In recent months, I have been speculating a bit about the impact those two pregnancies had on my medical condition. So that little snippet was particularly interesting to me because it suggests that having my second child likely left me with little islands of cells which lack my genetic disorder. I already have reason to believe that my pregnancies made me healthier, if only because of the degree to which throwing up for 8 months forced me to eat differently with my first pregnancy and many of those changes in diet became permanent. But this adds some real science to what has mostly been anecdata up until now.