"In one of the better-known investigations, boys and girls were asked to throw a softball with their dominant and then with their nondominant hands. Surprisingly, at almost any age, when they throw with their nondominant hands, boys achieve only slightly better scores than girls. And boys, no matter how well they throw with their dominant hands, tend to "throw like a girl" with the nondominant."
This of course can only mean one thing: girls have two left arms! This doesn't mean they can't train it to throw well... Overarm throwing is clearly serious business, and a lot needs to be taken into account.
The only remaining question is in a competition of throwing (poo?) who is best, Man or Monkey: "This research examined hand preference and postural characteristics of aimed throwing in capuchin monkeys and humans. We sought to directly compare the throwing performances of these primates, particularly the extent to which target distance influences hand preference, throwing posture, and throwing accuracy. For both species we found positive correlations between target distances for throwing accuracy, direction and strength of hand preference, percentage of bipedal vs tripedal throws, and percentage of overarm vs underarm throws. Throwing accuracy did not vary as a function of right vs left hand use although for monkeys throwing accuracy was positively associated with hand preference strength. We noted a sex difference among humans as males threw more accurately than did females. Between-species analysis indicated that humans exhibited greater right- vs left-hand use, greater hand preference strength, a greater relative percentage of bipedal vs tripedal throws, and a lower relative percentage of overarm vs underarm throws than did monkeys. We believe that the capuchin monkey is an informative nonhuman primate model of aimed throwing in humans and that research examining the throwing behavior of capuchins provides insight into the neurological and behavioral characteristics that underlie coordinated multi-joint movements across the primate order."