Microchimerism

"We may be more microchimeric than we imagined," says Dierselhuis, 

You may carry cells from siblings, aunts and uncles

• 14 June 2012 by Linda Geddes
• Magazine issue 2869.
• YOUR siblings may be closer to you than you thought. Male cells have been found in the umbilical cord blood of baby girls with older brothers, suggesting that the transfer of cells between mother and baby may be more extensive than previously imagined. Indeed, all of us may be walking chimeras.

Previous studies have shown that cells from both mother and fetus can cross the placenta during pregnancy, and survive for decades in the skin, liver, brain and spleen - a phenomenon called fetal microchimerism. There is even evidence that fetal cells may repair damage to the mother's heart during pregnancy.

Other studies have hinted that fetal cells might contribute to autoimmune disease, prompting speculation that fetal cells disperse more widely, possibly passing between siblings and even across generations./.../