Women retain and carry living DNA from every male with whom they have sexual intercourse, a new study conducted by the University of Seattle and the Fred Hutchinson Cancer Research Center shows.

The study, which found the above information by accident, was originally trying to discover whether women who have been pregnant with a son could be more predisposed to specific neurological diseases that occur more often in men.

However, as the scientists picked apart the female brain, the study started to veer wildly off course. As it turned out, female brains frequently harbor “male microchimerism“; in other words, there is a presence of male DNA that originates from another individual, and is genetically distinct from the rest cells of a female.

According to the study: “63% of the females (37 of 59) tested harbored male microchimerism in the brain. Male microchimerism was present in multiple brain regions.”

After discovering that 63% of women carry male DNA cells that live in their brains, the researchers wanted to explore where the male DNA came from.

As the researchers assumed through the study, the most likely answer was that all male DNA discovered living in the female brain came from a male pregnancy. However, when they autopsied the brains of women who hadn't even been pregnant, they still discovered male DNA cells prevalent in the female brain. Confused, the scientists needed to conduct further research to conclude that:

“Male microchimerism was not infrequent in women without sons. Besides known pregnancies, other possible sources of male microchimerism include unrecognized spontaneous abortion, vanished male twin, an older brother transferred by the maternal circulation, or sexual intercourse. Male microchimerism was significantly more frequent, and levels were higher in women with induced abortion than in women with other pregnancy histories. Further studies are needed to determine specific origins of male microchimerism in women.“

So as the scientists mention, the possible sources of the male DNA cells living in the female’s brains are:

-an abortion the woman wasn't aware of

-a male twin that vanished

-an older brother transferred by the maternal circulation

-sexual intercourse

As 63% of females have male DNA cells residing in the recesses of their brain, and since the first three options apply to only a very small percentage of situations, the most common source of the discovered male DNA cells is, apparently, sex.

What these scientists discovered is actually very interesting. Also, as the women autopsied in the study were elderly, the scientists also found that some of them had been carrying the living cells inside them for more than 50 years.

We are only now starting to understand the power and ramifications of sexual intercourse.

Sources:

-Male Microchimerism in the Human Female Brain

-Male microchimerism in women without sons: quantitative assessment and correlation with pregnancy history

-Ideaspots