Charlie said:
It's been done with other mammals, and I wouldn't be at all surprised if there aren't a handful of chimeric humans out there.
Apparently 8% of fraternal twins are "blood chimerae" because of cell exchange through a shared placenta. There are various other kinds of recorded chimerism. There are thirty or so known cases of tetragametic chimerism (i.e. one individual formed from two ova and two sperm). There are probably vastly more that have never been detected as they are externally normal (although some - such as true hermaphrodites - are more obvious). If I recall correctly, there are also cases of adults being formed of two ova and one sperm, including a boy whose bone marrow had only a mother and not a father.
Here's an article on the subject originally from New Scientist: http://www.katewerk.com/chimera.html Rich _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
