Redheads are stereotyped as fiery, unpredictable, impetuous and quick tempered. While the stereotype may have no basis in fact, there is a new study that shows redheads may require up to 20% more anesthesia than other women.

A new study at the University of Louisville reflected what many redheads have known for a long time. They apparently feel more pain than most people because of a quirk of genetics that is linked to having red hair.

The study used a common anesthesia on 20 women, 10 of whom were natural redheads. Then small electrical shocks were administered to the women. The redheads required more anesthesia to keep their bodies from reacting to the shocks, although none of them woke up.

Keep in mind, this was a small study and only women were tested. However, if you are a redhead facing surgery, you may want to have a talk with your doctor about the amount of anesthesia you should receive.