If George Bush invited former Beatles Paul McCartney and Ringo Starr and basketball coach Lefty Driesell to the same state dinner, he'd be asking for trouble. As a five-time winner of the Left- hander of the Year award, Bush should know better than to invite three more southpaws to a crowded dinner table. Say Ringo accidentally pokes the wrong righthanded ambassador while they're both eating steaming French onion soup. This could have global repercussions.

Why take such a "lefthanded" risk in a world where nine out of every 10 people are righthanded? Ever since the Romans adopted a righthand-only handshake, a left-to-right alphabet and the Latin words for right -- "dexter" as in dexterous -- and left -- "sinister" as in evil -- lefties have been viewed with suspicion.

Other languages have reinforced these negative connotations. Left in French is "gauche" (or awkward), in Italian it's "mancino" (or deceitful), in German it's "linkisch" (or clumsy) and in Russian it's "na levo" (or sneaky).

Our Anglo-Saxon "left" doesn't do them much better; taken from the Dutch "lyft," it means broken. Even the word "ambidextrous," generally used as a compliment meaning capable of using either hand efficiently is actually defined as "righthanded on both sides." The Bible, too, is replete with recitations of "the right hand of God" and its intimations of left being linked to Satan and "everlasting fire."

Is it all that amazing, then, that lefthanders are made to feel different in the classroom, where desks, scissors and notebooks are made for righthanders, and in the kitchen, where can openers, spouted pots and knife handles are right-made, and in the workshop, where left-to-right reading yardsticks, power saws and other tools are for right-handed people only? Even in sports, most baseball gloves, golf clubs, bowling balls and fishing reels are intended for righthanded use.

What does seem amazing is that no one really knows why people are lefthanded. Some have theorized that early humans were ambidexterous and that preference for the right hand began during the Bronze Age, when the use of tools became important. Ever since Plato gave it philosophical pause, the scientific research -- from Pasteur to modern-day experts like Canadian psychologist Stanley Coren has been fast and at times furious. Coren's conclusions that life expectancy is lower and accident-proneness higher in lefthanders created a furor last year, but he said his findings "do not provide any direct causal information."

A recent study at the University of Belfast in Northern Ireland indicating that fetuses overwhelmingly prefer sucking their right thumbs doesn't explain why.

"The problem with lefthanded research is that what causes lefthandedness could be one of 15 different things," says Jerre Levy, a professor of behavorial science at the University of Chicago whose research has focused mainly on the brain. Of the many theories, the one that hand preference is related to brain dominance not only seems most promising but is relatively enduring. As early as 1648, English physician Sir Thomas Browne first published his theory that lefthanders' ability was linked to the way their brains function.

"Lefthanded research is constantly finding links to the brain," says Suzan Ireland, editor of Lefthander Magazine, house organ for the 30,000-member Lefthanders International. "The same tags keep coming up. When we find the cause of lefthandedness, we'll know more about how the brain works, too."

Basically these theories hypothesize that people who are lefthanded are right-brain dominated. The brain is divided into two hemispheres, which, according to science writer Jack Fincher, "are as different as they can be.

"They differ so much functionally," writes Fincher in his book "Sinister People," "that many researchers have taken to calling them our 'two brains.' " Fincher's words are echoed by Levy's findings, which show that each brain hemisphere has distinctly different functions. The left side of the brain controls logic, linear thinking and verbal skills, while the right side controls visual skills and intuition. Each side also physiologically controls the opposite side of the body.

Here's where things get complicated. Lefthandedness may indeed be caused by right-brain dominance, but it is not the only factor. Other brain research has shown that a person's language function is also connected to choice of hand use. Most people -- righties and lefties -- have their language centers in the left-brain hemisphere. But the sizable disparity between righthanders and lefthanders with this arrangement -- 95 percent to 70 percent -- seems to indicate that lefthand dominance is not simply the converse of righthand dominance. Almost a third of the time, lefthanders have language centers in the right brain hemisphere or in both hemispheres simultaneously.

The only thing that seems certain is that the cause of lefthandedness lies somewhere in the complex web of nerve endings that connects the brain to the spinal cord and ultimately to the arms and hands.

This, however, leaves lots of room to roam theoretically. For example, because the right side of the brain controls a person's more artistic functions, some theories proclaim lefthanders to be more creative than righthanders. The roster of famous creative lefthanders includes Leonardo da Vinci, Ben Franklin, Lewis Carroll, Pablo Picasso, Cole Porter and Charlie Chaplin.

Barry Smith, a psychologist at the University of Maryland, adheres to two theories of handedness: first, that it is genetic, in that a person is predisposed to it at birth; the other, that it is environmental, that is, an overwhelmingly righthanded world helps shape handedness. "The two theories exist more or less in parallel," says Smith. "The best hope of resolving them is through genetic engineering, finding the responsible chromosome and nailing the cause down tight."

The reality is that lefthanders have to live in a righthanded world and adapt to it as best they can. Some research indicates that babies play with toys equally well with both hands but usually develop a preference before school age. Statistics show a 3-to-1 ratio of males to females among lefthanders. Among left-handed athletes who adapted superbly were baseball immortals Ted Williams and Babe Ruth, tennis stars Martina Navratilova and Rod Laver and Brazilian soccer player Pele.

The creative drive or the psychiatric problems that are attributed to lefthanders might be due, in Smith's opinion, to the extra adaptation required of them. According to Fincher, forcing lefthanded kids to switch to their right hands may be "tinkering with the fundamental organization of the brain." Often, the negative results of this far outweigh the hoped-for advantages -- anything from loss of spatial orientation to stuttering.

Regardless of the effects, millions of people have suffered since the time of the Romans because of prejudice against lefthanders. Countless horror stories note that children were punished for using their left hands and forced, often brutally, to switch to their right.

Thankfully, the stigma associated with lefthandedness is dying out. More common nowadays is the example of Karen Levy, 27, a schoolteacher who considers herself "a purebred lefthander." Says Levy, "I never got any pressure at home to change. I always thought of my lefthandedness as a blessing in disguise. It made me feel special. It also allowed me to play first base better than anyone else."

Levy is a first-grade teacher at Murch Elementary School in northwest Washington. Most of her students have already started writing by the time she sees them, but her teacher's manual includes instructions on how to teach writing techniques to both righthanders and lefthanders.

Since lefties generally have sloppier penmanship, an affliction Levy has noticed in her classroom and in her own writing, the manual recommends ways of placing the hand, paper and pen to correct this propensity. The most noticeable habit of lefthanders is that they "curl" their hands when they write, an instinctive trait that helps compensate for the left to right flow.

One of Levy's most prized possessions is a button that was given to her last year by one of her students. It says, "Hire the lefthanded. It's fun to watch them write."

Alan Bisbort is a writer in Arlington.