London, June 29: There's no need to scratch your chin to cultivate why Bollywood heartthrobs like Akshay Kumar and Abhishek Bachchan prefer flaunting stubble --well, it's the way to win a woman's heart, according to a new study.

Researchers in Britain have carried out the study and found that women are more attracted to men with stubbly chins than those with clean-shaven faces or full beards -- in fact, the fair sex prefers them for love, sex and marriage.

According to the researchers, stubbly men offer women the best worlds -- not too strongly masculine, but mature and with the potential to grow a full beard, British newspaper 'The Sunday Telegraph' reported.

"Facial hair or beardedness is a powerful sociosexual signal, and an obvious biological marker of sexual maturity," said lead researcher Dr Nick Neave of Northumbria University.

In their study, the researchers altered pictures of 15 men's faces so that they showed various degrees of hairiness, using latest computer technology. Five levels of facial hair were used -- clean-shaven, light stubble, heavy stubble, light beard and full beard.

The pictures were shown to 76 women who were asked to rate them for masculinity, aggression, dominance, age, social maturity and attractiveness. They were asked how desirable each man would be as a short-term or long-term partner.

The participants rated men with stubble as tough, mature, aggressive, dominant and masculine -- and as the best romantic partners, either for a fling or even for a long-term relationship, the researchers found.

Though faces with full beards were chosen to be the most masculine, aggressive and socially mature, they're rated the least attractive and worst choice for a short-term fling.

And what's surprising is that clean-shaven men finished bottom for masculinity, dominance, aggression, and social maturity, and they were the least favoured choice as a long-term partner. They're second-to-last for attractiveness.

"Facial hair may have been sexually selected by females on the basis of associated male success, despite its threatening appearance. Clean-shaven faces, therefore, suggest appeasement and being an obvious sign of sexual immaturity.

"Increasing levels of facial hair were associated with increased perceptions of aggression, in that bearded faces are perceived as being most aggressive, whilst clean-shaven faces were rated as being the least aggressive.

"And as facial hair increased in linear fashion so did female ratings of masculinity and dominance. In desirability for a short-term relationship, a female preference for male faces with stubble or light beard was found, with clean-shaven and fully bearded faces being the least preferred.

"This indicates that females are not selecting faces displaying relatively high or low masculinity, but rather prefer males who are clearly mature -- post-pubertal -- but not too masculinised. The same pattern was found for preferences for long-term relationship," the researchers said.

The results of the study have been published in the 'personality and individual differences' journal.