It’s not exactly the rarest hair color and eye color combination. So which combo is the least common? To understand that, we need to understand the science. As Julie Kaplan, MD, a physician at ...

Add hair color to that list, too. Calico hair is familiar for millennials, as it’s a recycled trend from chunky highlights of the early aughts, says Ryan Dickie, a colorist at IGK Salon Miami.