Physicians, like other professionals in society, stake out a scope of practice that gives them ownership rights to performing tasks within a specific clinical territory. Just as lawyers reserve exclusive rights to practice law and pharmacists to dispense pharmaceuticals, so also have physicians demarcated subspecialty lines. Oncologists are the cancer experts, obstetricians bring children into the world, pediatricians take care of children, and neurosurgeons perform brain surgery. These ownership rights constitute professional monopolies.