This is absolutely fascinating! From the Anchoress, via Happy Catholic:
http://happycatholic.blogspot.com/2012/08/modern-science-and-assumption-of-mary.html"When studying Anatomy and Physiology in college, the lesson that briefly discussed fetomaternal microchimerism, became instructive to me on a different level. Learning that every child leaves within his mother a microscopic bit of himself —
and that it remains within her forever — the dogma of the Immaculate
Conception instantly became both crystal clear and brilliant to me."