Left-handed Canadian golfer Mike Weir last month won the Masters at Augusta, Georgia - the most prestigious tournament on the Professional Golf Association (PGA) tour. He was the first Canadian to win the title, but what captured the world's attention was that Weir became the first left-handed golfer to don the green jacket. Being one of only six left-handed players on tour, Weir became the second left-handed golfer to win a Major championship (New Zealand's Bob Charles won the British Open in 1963). Interestingly, his opponent for the playoff hole, Len Mattiace, was originally left-handed but his father made him play right-handed. Weir wrote a letter at the age of 13 to his golf hero Jack Nicklaus asking whether he should learn to play right-handed. To his credit, the golf legend told Weir not to switch. Being left-handed in a right-handed world isn't easy. Many items such as scissors, cameras and corkscrews are built for right-handed people. The Latin word sinistral from which the word sinister is derived, means left-handed. Yet for sports that demand rapid reactions and good spatial judgment, being left-handed can be an advantage. According to Dr Martin Samuels, chief of neurology at Boston's Brigham and Woman's hospital, left-handers' brains are wired differently. The brain's two halves (hemispheres) perform different tasks. Some researchers believe these functions are more symmetrical or evenly distributed in left-handed people, resulting in more effective communication. Other researchers believe the brain's processing speed plays a role. A left-handed tennis player, for example, uses the right side of his brain to control movements and perform space management. This allows both sides of the brain to process a ball coming towards a player as well as returning the ball. A right-handed player has to transfer this visual information to the opposite hemisphere, adding reaction time. Other scientists believe the right hemisphere may be enlarged in left-handed people, therefore giving them greater spatial skills. Psychologists Charles Wood and John Appleton from Britain's Durham University believe the advantage is tactical and not neurological. For example, baseball values left-handed players, (often referred to as 'south paws') because of the unfamiliarity they create. A left-handed pitcher can keep a runner at first base more effectively because he faces the base. According to some top pitching coaches in the US, left-handers have to throw differently to cope in a right-handed world. They tend to release the ball lower than right-handed pitchers giving the pitches more movement. The same theory can be applied to cricket. Left-handed players bowl at a different angle and move the ball to the opposite direction to their right-handed counterparts. Five out of every 25 professional tennis players are left-handed. Some more famous lefties in tennis include Martina Navratilova, who won Wimbledon eight times in 10 years, John McEnroe, Jimmy Connors and Goran Ivanisevic. In tennis and squash, the tactical advantage of a left-handed player is well known. Players who hit a ball to their opponent's weaker backhand will only get a left-handed player's strong forehand. A left-handed player also has an awkward serve that swings away from the backhand of the right-hander. Although Weir made winning this year's Masters look easy, being a left-handed player has its challenges. Until recently, the only way a left-hander could get top-quality equipment was to have clubs designed. And all golf courses are designed for right-handed players by right-handed golfers. There are only 10 per cent of golfers who play left-handed - slightly less than the general left-handed population- because most left-handed golfers have switched to right-handed. Since the golf swing is not a natural move, changes are easily made. It's not the same as asking someone who writes left-handed to write with their right. For left-handers it may be as simple as being forced to play in a right-handed world that creates a psychological advantage. Whereas a right-hander may be at a disadvantage by knowing their opponent is a lefty.