ฺBut Pig 23 will serve human in a different way. He is beginning grown in the hope that animals like him might one day prove suitable organ donors for humans. In each of his cells, tucked in somewhere among 19 pairs of pig chromosome, is a bit of humanity gene. He might not look it, but Pig 23 and few dozen others like him may harbor the solution to one of the most vexing problems of modern medicine.