Like a priceless heirloom, a child can leave a trace of themselves in their mother's brain after birth.
The physical connection between a mother to her child and vice versa is deeper than we previously thought. It's more than just a child being cradled in the womb for nine long months. It's more than just the period of skinship and childrearing wherein a mother provides security and warmth to her child after birth.
In gestation, placenta through the attached umbilical cord connects the child to its mother. The placenta serves as a conduit of nutrients and mineral exchange. In this process, we've been exchanging cells with our mothers through what we call as fetal-maternal microchimerism. We may have gotten cells from our grandparents and even received cells from our older siblings that they've left to our mother after birth through this process.
A study found that "Y" chromosomes were circulating in the blood of women after birth which the women may have gotten from their son during gestation.
In a study reported in 2012, scientists found remnant of male cells embedded in the brains of 59 women who had died between the ages of 32 and 101. Daughters may have also left traces of themselves to their own mother but there is no way of tracing that yet. It is hard to distinguish a female DNA from the mother's genes, at least for now.
The 37 of the 59 women were found to have traces of the male Y chromosome in multiple regions of their brains. It was also found in a woman aged 94. That gave us an evidence that this effect is long-lasting.
The blood-brain barrier, which is our body's defense system keeps drugs and germs in the bloodstream from entering our brain. But during pregnancy this barrier becomes permeable. Scientists concluded this could be the reason why the fetal cells migrated to the mother's brain.
The DNA we leave out to our parents may have had an effect to their health, but whether negative or positive that is not yet apparent.
William Chan, an immunologistat the Fred Hutchinson Cancer Research Center in Seattle said, "We think it is likely that microchimerism imparts benefit in some, but in other situations may contribute to a disease process. Further studies are required."
The details of the study was published in PLoS ONE.
Mothers, the next time you miss your son don't forget you have always been keeping them in your head.