Microchimerisms. Microchimerism is a surprising phenomenon recently introduced in the biological terminology linked to the observation, that particular multicellular organism can harbour small numbers of cells that originated in a genetically different individual. There are several ways how independent individuals can mix up the cells. During pregnancy some cells traffic from the mother to the fetus and from the fetus to the mother. Surprisingly, a small number of the mother´s cells persist in her offspring, including into adult life and a small number of cells from prior pregnancies persist in mothers many years later. It has only recently become apparent that naturally acquired microchimerism is common in human. A number of medical research teams are currently investigating both food and bad consequences of microchimerism in human health and disease. Bad consequences could be linked with autoimunity, the good ones interest those developing reparatory approaches for demaged old bodies and transplantologists dreaming about breaking histoincompatibily limitations.