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Barack Obama is also left-handed as well as CLinton, and Reagan.
It was actually very interesting to read about left-handedness. Here are some of pieces of information from wiki:
Left-handedness (also known as sinistrality, sinistromanuality, or mancinism) is the preference for the left hand over the right for everyday activities such as writing. In ancient times it was seen as a sign of the devil, and was abhorred in many cultures. A variety of studies suggest that 10% of the world population is left-handed.
Causes
- People are not born left or right during the period of 6 months the brain decides dominance after birth.
- In 2007, researchers discovered that specific alleles of at least one of three single-nucleotide polymorphisms upstream of the already known LRRTM1 gene were linked to left-handedness.[3][4]
- Twins theory: this theory postulates that left-handed individuals were originally part of an identical twin pair, with the right-handed twin fetus failing to develop early in development. Although Australian researchers have debunked[5] the related Vanishing twin theory, it is yet unexplained why twin children have a high frequency of left-handedness / right-handedness in the pair.[6]
- Long-term impairment of the right hand: people with long-term impairment of the right hand are more likely to become left-handed, even after their right hand heals.[citation needed]
- PreNatal Hormone imbalances may play a role in the gene expression for left-handedness. While the Geschwind–Galaburda testosterone hypothesis is often cited as cause, there isn't any evidence to support the theory. However, more recent research has emerged suggesting that high prenatal estrogen exposure is a plausible alternative to Geschwind. In a study endorsed by the Centers for Disease Control (CDC), it is suggested that men who were prenatally exposed to diethylstilbestrol (a synthetic estrogen based fertility drug), are more likely to be left handed.[7]
Intelligence
In his book Right-Hand, Left-Hand,[29] Chris McManus of University College London argues that the proportion of left-handers is increasing and left-handed people as a group have historically produced an above-average quota of high achievers. He says that left-handers' brains are structured differently in a way that increases their range of abilities, and the genes that determine left-handedness also govern development of the language centres of the brain.
In a 2006 U.S. study, researchers from Lafayette College and Johns Hopkins University concluded that there was no scientifically significant correlation between handedness and earnings for the general population, but among college-educated people, left-handers earned 10 to 15 % more than their right-handed counterparts.[30]
Politics
Of the seven most recent U.S. Presidents, four, including Barack Obama, have been left-handed, while a fifth is said to have been ambidextrous: Ronald Reagan, who was left-handed by birth, became president after he defeated left-handed candidate George H. W. Bush in the Republican primary election. Four years earlier, Reagan had lost the Republican presidential primary to incumbent left-handed President Gerald Ford. George H. W. Bush succeeded Reagan and later ran for re-election against left-handers Bill Clinton[34] and Ross Perot.[33] Clinton's second term opponents included Perot, and Bob Dole who had become left-handed when his right arm was paralyzed in combat 50 years earlier. Left-handed then Senator Obama defeated left-handed Senator John McCain in his race for the presidency.[35]
Accessibility of implements and skills
People tend to have most strength and control in their lead hand - whether left or right. Because the vast majority of the world population is right-handed, most everyday items are mass-produced for expected use with the right hand. Tools, game equipment, musical instruments and other items must be specially ordered for left-handed use, if they are available at all.
Many left-handers adapt themselves well to a right-handed world. While writing may necessarily remain with most a left handed function necessitating a considerable degree of control, other two handed functions may well be done in a right handed manner (eg: holding cricket and baseball bats, golf clubs, holding both knives and forks when eating). Left-handedness will always be far more apparent in one-handed operation (eg: tennis rackets, table tennis bats, javelin throwing, Ball and shot throwing etc.)
Right-handed tools may be difficult or uncomfortable to use for some people who are left-handed unless they have learned to adjust. For example, (right-handed) scissors are arranged so that the line being cut along can be seen by a right-handed user, but is obscured to a left-handed user. Furthermore, the handles are often molded in a way that is difficult for a left-hander to hold, and extensive use in such cases can lead to varying levels of discomfort. Ambidextrous scissors will mold the handles to be the same shape, but will not reverse the position of the blades. Most importantly, the scissoring or shearing action - how the blades work together (how they are attached at the pivot) - operates correctly for a right-hander, but some left-handers may tend to force the blades apart rather than shearing the target substance.[18] Left-handed scissors require inverting both the handles and the blades if the left-handed user is to fully see the progress of the cut. Right-handed scissors place the thumb's blade on the left side, while left-handed scissors have this on the right side. This ensures the left hand's motion draws the blades together while cutting, ensuring a cleaner cut.
Other handed items which could prove to be inconvenient for left-handers include cameras, train-station turnstiles, can openers, potato peelers, corkscrews, rulers, computer mice and keyboards, watches, chequebooks, spiral notebooks, lever arch files, fishing reels, boomerangs, measuring cups and pencil sharpeners.
Left-handed adaptations have even bridged the world of music. Left-handed guitars are manufactured as an alternative to using a flipped around right-handed guitar. There have even been inverted pianos where the deepest notes correspond to the rightmost keys instead of the leftmost.[19] Inverted trumpets are made, too. Although most brass instruments' main valves are designed to be operated with the right hand, the prevailing belief is that left-handed performers are not at a significant disadvantage. The French horn is played with the left hand, and there is no evidence that right-handed performers are at a disadvantage on that instrument.
A left-handed individual may be known as a southpaw, particularly in a sports context. It is widely accepted that the term originated in the United States, in the game of baseball.[20] Ballparks are often designed so that batters are facing east, so that the afternoon or evening sun does not shine in their eyes.[21] This means that left-handed pitchers[22] are throwing with their south-side arm.[23] The Oxford English Dictionary lists a non-baseball citation for "south paw", meaning a punch with the left hand, as early as 1848,[24] just three years after the first organized baseball game, with the note "(orig. U.S., in Baseball)."[25] A left-handed advantage in sports can be significant and even decisive, but this advantage usually results from a left-handed competitor's unshared familiarity with opposite-handed opponents. Baseball is an exception since batters, pitchers, and fielders in certain scenarios are physically advantaged or disadvantaged by their handedness.
The vast majority of firearms are designed for right-handed shooters, with the operating handle, magazine release, and/or safety mechanisms set up for manipulation by the right hand, and fired cartridge cases ejected to the right. Also, scopes and sights may be mounted in such a way as to require the shooter to place the rifle against the right shoulder. A left-handed shooter must either purchase a left-handed or ambidextrous firearm (which are manufactured in smaller numbers and are generally more expensive and/or harder to obtain), shoot a right-handed gun left-handed (which presents certain difficulties, such as the controls being improperly located for the left hand or hot shell cases being ejected towards the shooter's body, especially the eyes or down the collar or right sleeve), or learn to shoot right-handed (which may be less comfortable, feel "unnatural", and probably less effective). A related issue is ocular dominance, due to which left-handed people may wish to shoot right-handed, and vice versa.
Lever action and pump action firearms present fewer difficulties for left-handers than bolt action weapons do. Many weapons with adjustable sights allow for left-handed use, but for a right eye dominant shooter it is necessary to adjust. In fact, most weapons adjust well enough that a weapon will not eject shells into a left-hander's eye. However, some bullpup style rifles, such as the L85, cannot be safely fired left-handed at all, being that the empty cases would be ejected directly at the shooter's face.
Power tools, machinery and other potentially dangerous equipment is typically manufactured with the right-handed user in mind. Common problems faced by left-handed operators include the inability to keep materials steady, and difficulty reaching the on/off switch, especially in emergency situations.[26] A further factor is the relative strength of the lead hand and arm. A left handed person will tend to have less physical strength in the right hand and arm, and vice versa. So while heavy tools may necessarily have to be held in the right hand due to the handed-ness of the tool, there will be less strength in a left handed person to control and guide the tool.
Handheld circular saws are made almost exclusively for right-handers, with the motor and grip on the right side. If held in the left hand, it is impossible for the operator to see what they are cutting and sawdust will be thrown out to the right towards the face and eyes, rather than away from it. Tool manufacturer Porter-Cable produces a left-handed circular saw that can be purchased relatively inexpensively.[26]
Also, in some countries classrooms and offices are designed to maximize the use of natural light by placing desks so that the windows are on the left. This often creates inconveniences for left-handers as the shadow of their left hand with the pen makes it harder to see the text being written.
One of the few items in common use that is actually advantageous for left-handers is the QWERTY keyboard. Over 3000 words in English can be typed with only the left hand on the QWERTY board as opposed to some 300 with the right hand, and overall, 56% of the keystrokes made when touch-typing on a QWERTY board are made with the left hand.[27]
But I've heard that both hands can carry out the same things 
