Older siblings' cells can be passed from female dogs to their puppies in the womb

Researchers have found that microchimerism, a condition where some people possess a small number of cells in their bodies that are not genetically their own, can be passed from a female dog to her offspring while they are still in the womb. Microchimerism most often occurs when a mother gives birth to a child. In some cases, cells from that child are left in the mothers' body and continue to live, despite being of a different genetic makeup than surrounding cells. Researchers have identified evidence that those cells can then be passed on to other children the mother may give birth to at a later time.