Tall men attract the ladies because they remind them of our violent ape-like ancestors, according to a new theory.
A study shows men hit harder when they stand on two legs than when they kneel down, and when directing punches downwards.
This might explain why early humans began walking upright, and also why women prefer tall men, say US researchers.
Professor David Carrier, from the University of Utah, said: "The results of this study are consistent with the hypothesis that our ancestors adopted bipedal posture so that males would be better at beating and killing each other when competing for females.
"Standing up on their hind legs allowed our ancestors to fight with the strength of their forelimbs, making punching much more dangerous. It also provides a functional explanation for why women find tall men attractive.
"Early in human evolution, an enhanced capacity to strike downward on an opponent may have given tall males a greater capacity to compete for mates and to defend their resources and offspring. If this were true, females who chose to mate with tall males would have had greater fitness for survival."
The findings are reported in the online journal Public Library of Science ONE.
Prof Carrier's team measured the force of punches delivered by male boxers and martial arts experts as they hit in four different directions, forwards, sideways, down and up.
For all punching angles, the blows were much harder when delivered standing up rather than kneeling down, and the men could hit three times harder punching downward.
Many studies have shown that women find tall men more attractive. But Prof Carrier disagrees with the theory that this is chiefly because height indicates "good genes" which may be passed onto offspring. "If that were the whole story, I would expect the same to be true for men - that men would be attracted to tall women," he said. "But it turns out they're not. Men are attracted to women of average height or even shorter."