Scientists have, over the years, found that attractive faces tend to be shaped like ovals or inverted triangles, rather than circles or squares, and satisfy certain mathematical rules.
Attractive faces tend to be symmetrical, left and right, and have a height-width ratio of about 1.618, famously known as the Golden Ratio.
Vertical distances are also evenly proportioned, with the hairline, inner tips of the eyebrows, bottom of the nose and tip of the chin at equal distances apart.
Dr Wong Chin Ho, a surgeon at W Aesthetics Plastic Surgery (Mount Elizabeth Novena Specialist Centre), said the optimal proportions apply whether one is male or female, and Asian or Caucasian. It is the variations in detail that differentiates between gender and race, he added.
For example, males tend to have a more prominent brow, higher nose bridge, wider cheeks and more angular jaw, which Dr Wong likened to the way Superman and Batman are depicted in comic books.
However, Dr Elias Tam, medical director of EHA Clinic, said some men in Singapore prefer a more androgynous face with a less prominent jawline and chin, following the trend in South Korea.
Dr Wong noted that other traits such as the shape of the eyes, nose and lips also play a part. "It is the harmony between the various parts of the face that determines its beauty as a whole. This perception is so instinctive that even children can tell what is an attractive face and what is not," he said.
Aesthetic doctors also acknowledge that there is some variation in what people of different ethnicities and cultures perceive as attractive.
For example, a study by Korean researchers in 2010 found that an attractive Japanese face is long with slightly slanted eyes, chubby cheeks and a sharp chin, an African one has a relatively narrow nose, smaller eyes and upper lip, and a slender chin, while an attractive Caucasian face is somewhat masculine.
In what it says is the first use of science in a beauty competition, international treatment provider Merz Aesthetics is using mathematical proportions to search for the most beautiful face in each of the 10 Asian countries, including Singapore. For more information, visit www.goldenratiosearch.com.