Although it cannot be used as evidence of doctrine, modern scientific research and studies sometimes offer remarkable insight into the unique bond between the Blessed Virgin Mary and her Divine Son, Jesus Christ.
According to Catholic teaching, the Immaculate Conception was a singular act of divine grace in which Mary, from the first moment of her conception, was preserved from Original Sin in view of the merits of Jesus Christ. The Spanish Jesuit theologians Iesu Solana and J.A. de Aldama, famous for contributing to the esteemed Sacra Theologiae Summa manuals, provides insight into the theological reasoning behind this sublime mystery:
[B]ecause this miraculous maternity according to the divine plan had to remain for a time hidden from men, it was necessary that the Son of the Virgin Mother be born within the confines of a legitimate marriage. Hence a spouse [Saint Joseph] had to be given to her, with whom she was joined in Holy Matrimony.1
While Catholics accept — or rather, are obliged to accept — the Immaculate Conception as a dogma of faith, research into pregnancy in recent years has revealed remarkable data that may deepen our contemplation of the physical intimacy between a mother and the child she bears, and therefore between the Blessed Virgin and her Son, Our Lord Jesus Christ.
Studies on women during pregnancy
Scientists define fetal microchimerism as “the long-term persistence of a small population of cells that originate from a genetically distinct individual.”
According to pregnancy research, a small number of cells from the unborn child can actually cross into the mother’s body. Some of these cells do not disappear after birth and remain for decades — even for life.
On X this week, user Anish Moonka highlighted past research that has been conducted on the topic. Catholics who read his post argued that the research supports Church teaching on Mary’s Immaculate Conception.
During a 2012 study conducted by the Fred Hutchinson Cancer Center, researchers examined the brains of 59 deceased women and found male DNA in thirty-seven of them, a full 63 percent of the sample. In several cases, the women had lived into old age. The study concluded that a previous pregnancy with a male child was the most likely explanation, while taking other factors into consideration as well.
Other microchimeric studies suggest that cells from the child may later travel to sites of injury and participate in tissue repair for the mother. “Male–presumed fetal cells in healed maternal CS (Caesarean-section) scars after pregnancy suggests that … fetal cells migrate to the site of damage to become involved in maternal tissue repair, or proliferate locally,” a 2014 report found.
In 2025, a team of researchers at Cincinnati Children’s hospital observed that, in some cases, “these persistent [fetal] cells are not accidental souvenirs of pregnancy, but play a surprising role in helping mothers ‘remember’ previous pregnancies.”
What this essentially means is that a child does not simply dwell for nine months within his or her mother’s womb and then depart without trace, but that a small part of their actual body may remain within her.
The Dispatch
Later in his X post, Moonka said that another study of 177 women found that “fetal cells appeared in the blood of 85 percent of the healthy participants.” He also said that a “French team looked at umbilical cord blood in 2021 and found cells belonging to the baby’s grandmother in 5 of 28 samples. Cells that crossed one placenta decades earlier had crossed a second one [later].”
Fetal microchimerism and Church teaching
When viewed in light of the Catholic faith, these studies compel us to reflect more deeply on the Blessed Virgin Mary and her pregnancy of Our Lord, who took His human flesh from her.
Mike Parrot of RTF Media drew attention to this on X, crucially noting that “Her body would necessarily be free of original sin because she would have carried the biological material of our Blessed Lord all the way through to her heavenly assumption.”
Building on this point, commentator James the Catholic highlighted that the “pull” a mother has toward her child is due to, among other things, the fact that her child’s cells are physically living within her.
Other social media users made similar theological-minded remarks.
“Microchimerism is a large reason I came to accept the perpetual virginity and her Immaculate Conception,” account RachelToRome said. “God wove it into the fabric of creation that a woman would take on her children’s DNA and be changed by it … It seems very clear to me also that Mary had to be free from original sin to bear God Himself in her womb.”
User John Wright likewise said, “the body and blood of the Savior was in the body of the Virgin Mary.”
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In his Glories of Mary, St. Alphonsus Liguori explains that God prevented Our Lady from the stain of original sin because it would have been unfitting for the womb that was to bear the Savior to have ever been corrupted by the evil one. The research and studies referenced above on fetal cells and the physical exchanges that take between a mother and her unborn child clearly provide “proof,” albeit scientific, for the Immaculate Conception.
- Sacra Theologiae Summa, II-A (trans. Kenneth Baker), 1955, p. 358. ↩︎
