In 1953 a human chimera was reported in the British Medical Journal. A woman was found to have blood containing two different blood types. Apparently this resulted from her twin brother's cells living in her body.[14] More recently, a study found that such blood group chimerism is not rare.[15]
I've long believed (since early 90's, when I first learned about DNA tests and molecular biology) there are a collection of phenomena that make the common assumptions in DNA forensic testing much less firm than ... well, the users of those products assume.
