It was not a color most women would wear, but it brought out the reckless gleam in her long straight hair and the green of her eyes.

Dr. Neitz, who conducts his research with his wife Maureen, said only women have the potential for super color vision.

A tetrachromat has another type of cone in between the red and green (somewhere in the orange range) and its 100 shades, theoretically, would allow a woman to see 100 million different colors.