Chimerism - a useful article

This article discuses chimerism:

Chimerism is a strange beast. Scientifically, it’s the persistence of cells from two (or more) people in one body. Firm numbers remain elusive, but most—if not all—humans are probably a little chimeric, since mothers and fetuses commonly exchange cells during pregnancy. Such chimeric cells can invade organs throughout the body, including the brain, and scientists have found tantalizing links between chimerism and autoimmune diseases, in which the body’s immune system attacks its own tissue. Beyond strictly medical issues, chimerism also raises psychological questions about child development, sexual identity, mother-child bonding, and even what constitutes the self.

Many individuals who are not a twin may be chimeras because they pnoce had a twuin and the cels of the lost twin are the only thing that remains of their twin. I think this is very common and underestimated as a factor in auto-immmue disease, such as MS. People with MS should do the womb twin survivor test to find out more! See the new free PDF ebook for details

A good place to start your investigations! And it's free!