Twilight star Robert Pattinson is the world's sexiest men, apparently for anthropological reasons.

A new study implies that women find Pattinson attractive, not only for his on-screen vampire fangs, but also for the star's lean physiques. Anthropologist Barnaby Dixson conducted a study on what the sexes find attractive in the opposite sex based on history and across cultures.

The results concluded that women preferred a lean, less muscle-bound physiques like Robert Pattinson's.

"On a biological level, women are more likely to pick a leaner, even slightly more effeminate man as they equate those physical traits with being more caring and gentle and therefore a better prospect as a partner," Dixson said.

Pattinson was recently named by Glamour as sexiest in the magazine's 50 Sexiest Men poll. The magazine said Robert Pattinson benefited from his Twilight vampire character Edward Cullen.

"Women are attracted to vampires because of the element of danger that comes with them," said Glamour. "They are the ultimate bad boys - and women want to tame the beasts."

It's interesting to note that on-screen rival Taylor Lautner, who plays muscle-clad werewolf Jacob Black in the Twilight books, comes in at number 2 in the poll. Dixson may be right after all.