In the news: Baby's lingering cells

I caught an interesting science story on NPR this morning. Apparently, after a pregnancy, a woman ends up with a bunch of fetal cells in her body, and these cells linger in the woman for decades. What do these cells do? One idea is that they have some connection to autoimmune diseases, which women are more likely to develop. Another idea is that they serve as a supply of therapeutic stem cells, stepping to repair tissue damage when needed:

Some scientists have proposed that when a woman has a baby, she gets not just a son or a daughter, but a gift of cells that stays behind and protects her for the rest of her life. That's because a baby's cells linger in its mom's body for decades and -- like stem cells -- may help to repair damage when she gets sick. It's such an enticing idea that even the scientists who came up with the idea worry that it may be too beautiful to be true.

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