Re: Does the fetus' blood originate from the mother or father?

Hi - The answer is, "neither." Fetal blood originates from fetal cells. Each one contains a copy of maternal and paternal DNA. The process by which precursors, called stem cells give rise to mature or "differentiated" blood cells (red blood cells, white blood cells..) is called hematopoiesis. Early in development this process takes place in the yolk sac, then moves to the fetal liver. Soon after birth these cells migrate to the bone marrow where normal blood cell development continues throughout life.