Being left-handed can put you at a significant disadvantage financially that is really quite sinister. In fact the median income for a left-handed American worker is $1,300 a year less than that of a righty -- approximately a 6% income gap. And southpaw men have it worse: they earn a median annual income $2,500 less than their dexterous male counterparts. All this, according to research from Joshua Goodman of Harvard's Kennedy School published in the Journal of Economic Perspectives. The less robust earnings has nothing to do with lefties' physical abilities; in fact, lefties are more likely to be engaged in manual labor occupations. Goodman says the difference is a cognitive factor, related to language processing.