These are the most attractive female lips in the world, according to science

Angelina Jolie, Rosie Huntington-Whiteley, Kylie Jenner – all women of monumental influence, and all known for their seriously seductive lips. But while these A-listers might instantly come to mind when you think about what kind of lips are most attractive, a new study might just prove the contrary...

Researchers from the University of California sought to study different lip types to find what people like most. Published in the JAMA Facial Plastic Surgery medical journal in February last year, it found that although there is an "ideal" lip size and ratio, it's not what we commonly associate with sexy lips.

Researchers showed more than 400 participants a series of images of young (Caucasian) women and asked them to rank which photo, on a scale of one to 10, they found most attractive. The composite images were created with a computer-generated "synthetic morph" to change the proportions of lips on the same women. In this way, the focus groups were able to distinguish exactly which lips they found most attractive.

First off, a series of photos were shown of a woman whose overall lip size in comparison to the rest of her face was altered. This helped researchers understand what the "ideal" lip surface area was.

Credit: JAMA Facial Plastic Surgery

Secondly, the participants were shown images of a woman who had her upper and lower lips separately manipulated in size in order to try to figure out the "perfect" ratio between both lips.

Credit: JAMA Facial Plastic Surgery

Well, which did you think were most attractive? It might add up with the researcher's results, who found that the majority of participants preferred lips that were about 50 per cent larger than her natural lip size (the middle picture), and that took up around 10 per cent of the lower third of a woman's face. Participants preferred the first picture in the second set of images, revealing that people find a lower lip that is two times the size of the upper lip most fetching.

Co-author of the study Natalie Popenko told TODAY that models like Miranda Kerr and Alessandra Ambrosio both sport that kind of lip. The study noted that as well as being full (but not too full), people like well-defined lips because both of those things suggest youth and attractiveness. Fellow co-author Brian Wong, MD, PhD, told TODAY that what we consider attractive is heavily rooted in biology, with our primal instinct to procreate at the core of our perceptions of attractiveness.

What's interesting is that preferences for a Miranda Kerr type lip conflict with current plastic surgery trends. While the research found that people prefer a more natural look, "unfortunately, some celebrities are trying to create a trend that violates that aesthetic," says Wong. Many women often ask for a fuller upper lip when getting cosmetic surgery, but Wong warned that such procedures can often lead to the upper lip looking "overly filled and disproportionate".

Popenko implored that we shouldn't get obsessed with thinking there is such a thing as a "perfect" set of lips though. "Whole faces are greater than the sum of their parts and attractiveness can also be defined by unique facial features," she said.

Whether you love your natural lips or like to exaggerate them with a little help from Kylie's Lip Kits (or something else) – it's up to you to decide what you like best.