From a pretty overheated Associated Press article about stem-cell research and the commingling of species:

“But the biological co-mingling of animal and human is now evolving into even more exotic and unsettling mixes of species, evoking the Greek myth of the monstrous chimera, which was part lion, part goat and part serpent.

In the past two years, scientists have created pigs with human blood, fused rabbit eggs with human DNA and injected human stem cells to make paralyzed mice walk.

Particularly worrisome to some scientists are the nightmare scenarios that could arise from the mixing of brain cells: What if a human mind somehow got trapped inside a sheep’s head?

The ‘idea that human neuronal cells might participate in ‘higher order’ brain functions in a nonhuman animal, however unlikely that may be, raises concerns that need to be considered,’ the academies report warned.”