Raises the interesting possibility of undoing an abortion.
Mmmm... not exactly, since if you got one of those microchimera cells to develop into a xygote, the xygote would be the identical twin (or clone) of the aborted child, not the aborted child himself.
You can’t :undo” an abortion by cloning a cell from the baby any more than you could “undo” the murder of, say, Vince Ferrer by cloning one of your cells.