It has been estimated that left-handed people make up somewhere between 5 and 20 percent of the population. The reason for such a wide estimate is because nobody collects data on handedness. Think about it. Did you ever fill out a form for a physical examination or for a driver's license or for a census taker that asked which hand you use? About the only time this was a concern was went the military was ordering gloves for troops stationed in northern areas and needed to know which trigger finger - right or left - needed to have an opening. They determined the number of left-handed troops was between 7 and 11 percent.
But whatever the number, it's something that's built into the brain and nervous system. Handedness is not a choice and babies show a preference right from the time they're born. Parents who try to effect a change meet with mixed results and sometimes wind up with an ambidextrous child. Interestingly enough, studies of prehistoric sites suggest that our earliest ancestors may have been left-handed and that the switch occurred as language skills developed over many thousands of years.
Physically, humans show a number of bilateral preferences besides left and right-handedness. Individuals also tend to favor one eye and one ear and, placed with their back to a wall, will more often than not start out with the same foot. To get an idea of just how complicated the neural wiring for all these body parts actually is, just try walking and swinging your arms to match your legs. It's also been shown that people tend to use the two halves of their face differently. When full frontal portraits are taken, split down the middle and joined with mirror images, the combination of two left sides when compared with two right sides will look like two different people.
In terms of personality differences, the evidence is mostly anecdotal but left-handed people do appear to be more creative. This may be because the left half of the brain is associated more with logic and reason while the right half is associated more with art and inventiveness. If this seems the reverse of what it should be, remember that each of the brain's hemispheres control the opposite side of the body. However, human behavior is seldom as simple as it may seem and in one study of professional artists it was found that while paintings (2 dimensions) were more often done by righties, sculptures (3 dimensions) were more often done by lefties. I've also been told that those who sculpt are better dancers than those who paint but here again, this is strictly anecdotal.
Perhaps the strangest thing regarding handedness is how it's been viewed in different times and places. Mostly, left-handers have found themselves at a disadvantage. From cars and telephones to scissors and refrigerator doors, the modern world is made for right-handed people. But in the past, superstitious fervor sometimes caused lefties to be concerned for their health and wellbeing as such a preference was associated with witches and warlocks, black magic and evil. Even today, this connection is apparent in words like sinister and gauche - derived from the Latin and French words for left. And just think of all the common expressions that show an innate prejudice: out in left field; do it the right way; a left-handed compliment and that's right nice of you are all examples. When you get right to it, southpaws may well be our most openly maligned minority.