By the numbers: What are the most attractive female lips?

In the study by Brian J.F. Wong, M.D., Ph.D., of the University of California, Irvine, and coauthors, faces of white women were ranked by attractiveness with varied lip surface areas created for the faces and upper to lower lip ratios manipulated.

As it turns out, lips with a 53.5 percent increase in surface area from the original image with a 1 to 2 ratio of upper to lower lip that make up about 10 percent of the lower third of the face were deemed to be the most attractive, according to the results.

The study noted limitations, including that because there is no established reference range for total lip surface area modification in the general population, the surface area percentage reduction and augmentation extremes in the morphed faces were generated based on clinical experience of what seemed to be feasible.

"We advocate preservation of the natural ratio or achieving a 1:2 ratio in lip augmentation procedures while avoiding the overfilled upper lip look frequently seen among celebrities," the study concludes.