Only unmarried female physicians, who worked longer hours, earned more than their married counterparts with children, but their added earnings did not buy greater happiness.

Rather, the study says: "Most physicians are independent and earn their incomes by fee-for-service.

The physician who ran the farm's for-profit blood bank, for instance, earned between $130,000 and $150,000 per year off of inmate donations that he sold to hospitals.

"Five years ago, many physicians were earning over $1 million per year on drug sales alone," Mr. Straus said.

It would lead people to believe that physicians do not earn much more than the rest of us earn.

This is a continent where many physicians just earn $400 or $500 per month.

Of that, the company pays the doctors $5,000 to $7,500 several times what physicians earn for conventional prostate cancer procedures in the United States.

But veterinarians now average $70,000 to $80,000 a year, veterinary groups report, while physicians can easily earn $150,000 a year.

Many physicians, attorneys and corporate executives also earn incomes that enable them to achieve great wealth - particularly if it's managed wisely.

But most sequential physicians earn more than $50,000 and some more than $70,000.