According to the American Medical Association, 18 percent of doctors in the United States are over age 65.
A new study has found that, for certain procedures, patients may be at a higher risk when they're operated on by older surgeons who no longer perform a large number of surgeries.
The study also raises the difficult question of when doctors should retire.
It's a question that is especially pertinent for surgeons, but it's also an issue for any doctor.
The study is published in the current issue of Annals of Surgery.
It found that for surgeons over age 60, in three of eight operations, their patients had a higher mortality rate than the patients of surgeons age 40 to 50.
The three operations in which the study found an increased risk were: removal of pancreas, which has a 67 percent increased risk for patient death; carotid artery surgery, which is surgery on the main artery in the neck and has an increased risk of 21 percent; and coronary bypass surgery, which has the increased risk of 17 percent.
ABC News' medical contributor Dr. Tim Johnson said it was important to note that the increased risk of death was largely restricted to surgeons who performed fewer operations.
With surgery, practice tends to make perfect, Johnson says, so it's important to consider not just the age of a surgeon but also the number of operations a doctor performs a year.
What Do You Need to Know When Choosing a Doctor?
When choosing a pediatrician for your little one, you want a doctor with a lot of experience, not one fresh out of medical training.
When it comes to surgery or other medical procedures, a doctor's physical skills are very important, so age is more of a factor.
The best way to choose a surgeon is to find out about his or her outcomes -- how often they perform the surgery you need, what the results were, and what the death rate is.
Both doctors and hospitals track this information so it should be easy to get that information.
For more information, you can check the following Web sites: