This incidence was identified as a fetal microchimerism, after the chimera, a monster in Greek mythology that consists of different parts of lion, goat and dragon.
Several researches evaluated the cells left behind by sons regarding fetal microchimerism, due to ease for its discrimination from the cells of their mothers (5).
Fetal microchimerism and maternal health: A review and evolutionary analysis of cooperation and conflict beyond the womb.
Fetal microchimerism substantiates that heterologous prenatal adoption, even if done with a noble intention to save the child's life, is incapable of being oriented to God or human flourishing.
Hence, the placental immune suppression which is needed to maintain the allogeneic pregnancy also helps establish fetal microchimerism.
64) Fetal microchimerism persisted for more than twenty-seven years in one woman (65) and is believed to remain for the whole lifetime of postpartum women.
69) Although maternal-fetal microchimerism results in lesser amounts of cell and DNA transfer than what occurs in fetal microchimerism, (70) the amount of maternal cells found in healthy fetuses is still significant.
Researchers originally believed that fetal microchimerism caused various pathologies in women, especially immunological diseases: "By 2000, evidence of the presence of Y-bearing cells in women with diseases was mounting and the 'bad fetal cell' hypothesis was gaining momentum.
Parous women with fetal microchimerism are significantly less likely to develop cancer than parous women not harboring fetal cells.
Even in cases when heterologous embryo transfer occurs without seminal fluid priming, spousal one-flesh union is violated through fetal microchimerism.
However, a valid objection may be posed: If fetal microchimerism that results from heterologous embryo transfer violates spousal one-flesh union, would not the pluripotent chimeric cells from a non-spouse introduced into a married woman through a blood transfusion or organ transplant do so as well?
Fetal microchimerism that flows from a quasi-sexual act--as in the case of heterologous embryo transfer following IVF--violates the sexually exclusive one-flesh union reserved to spouses.