If you are wondering why women tend to prefer tall men, here is the answer.
According to a University of Utah study, men hit harder when they stand on two legs than when they are on all fours, and when hitting downward rather than upward, giving tall, upright males a fighting advantage.
This may help explain why our ape-like human ancestors began walking upright and why women like tall men.
While biology professor David Carrier' study primarily deals with the evolution of upright posture, it also may have implications for how women choose mates.
Multiple studies have shown that women find tall men more attractive.
Greater height is also associated with health, social dominance, symmetrical faces and intelligence in men and women.
These correlations have led some scientists to suggest that women prefer tall men because height indicates "good genes" that can be passed on to offspring. Carrier believes there is more to it.
"If that were the whole story, I would expect the same to be true for men - that men would be attracted to tall women. But it turns out they're not. Men are attracted to women of average height or even shorter," said Carrier.
The alternative explanation is that tall males among our ancestors were better able to defend their resources, partners and offspring. If males can hit down harder than they can hit up, a tall male has the advantage in a fight because he can punch down to hit his opponent's most vulnerable targets.
Carrier certainly is not saying women like physically abusive men or those who get into fights with each other. He is saying that women like tall men because tallness is a product if the evolutionary advantage held by our ancestors who began standing upright to fight.
"From the perspective of sexual selection theory, women are attracted to powerful males, not because powerful males can beat them up, but because powerful males can protect them and their children from other males," said Carrier.
"In a world of automatic weapons and guided missiles, male physical strength has little relevance to most conflicts between males," he added.
"But guns have been common weapons for less than 15 human generations. So maybe we shouldn't be surprised that modern females are still attracted to physical traits that predict how their mates would fare in a fight," said Carrier.
The study is detailed in the Public Library of Science journal PLoS ONE.