It's hard to pinpoint what distinguishes a gorgeous face from an average one, but some researchers are getting pretty close.
Psychologist Dr. Lisa DeBruine of the University of Aberdeen in Scotland says she's found that female faces become more attractive to men when the women are ovulating. "We think that the women might look healthier, have a bit of a healthier glow when they are ovulating," Dr. DeBruine says.
Symmetry is another factor that determines a face's attractiveness. Dr. Kendra Schmid, an assistant professor of biostatistics at the University of Nebraska Medical Center, says there is a equation for the "perfect" face. She uses 29 different measurements to determine someone's appeal on a scale of 1 to 10.
Find out how to measure facial perfection.
Dr. Schmid says the ratio of the length of the face to the width of the face should be 1.6, also known as the "golden ratio."
Whose face is the most "perfect," according to Dr. Schmid's measurements? No big surprise here! "Brad Pitt's is the highest [celebrity] that I've ever used the [formula] on," she says. "He was a 9.3."
Most people rate about 4 to 6. "There's never been anyone who was a perfect 10," Dr. Schmid says. "If you're out there, we're looking for you!"