According to a report from New Scientist, most people appear to carry cells that originated from their mother and crossed the placenta into the developing brain in utero. The finding points to a form of maternal-fetal microchimerism that is far more widespread in the brain than previously recognized.
The report indicates that these maternal cells have been found even in individuals now in their 80s, suggesting they can persist for a lifetime. While the functional role of these cells is not yet clear, their long-term presence raises questions about how maternal biology may influence brain development and aging.
Because only one source was reviewed, there are no conflicting findings to compare. The main limitation is that the report does not specify the size of the study or the methods used to identify the cells, so the broader significance remains to be confirmed by further research.