What is most revealing about the first paragraphs of the article is that there is no mention of where those transferred cells end up in Mary’s body.
Cells in our bodies are highly specialized making up various tissues and organs. Even in pregnancy, what gets exchanged between the mother and fetus are highly regulated and occur strictly within specific physical channels. There cannot be random transfer of cells outside of those channels.
Besides, our bodies renew itself in its entirety replacing all the cells every 7 years or so. Whatever foreign cells that survive the body’s defense mechanism (highly unlikely) simply cannot still be there after about a decade.
I've heard this; but then WHO is that OLD fella in my mirror?