I wonder why they didn't mention male microchimerism, a still poorly understand phenomenon, in which male DNA is found in females. Possible sources of gene tra

I wonder why they didn't mention male microchimerism, a still poorly understand phenomenon, in which male DNA is found in females. Possible sources of gene transfer are " unrecognized spontaneous abortion, vanished male twin, an older brother transferred by the maternal circulation, or sexual intercourse" https://www.ncbi.nlm.nih.gov/pubmed/16084184/ https://www.ncbi.nlm.nih.gov/pubmed/16084184/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3458919/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3458919/