Pretty interesting observation. Based on your PR friend's experience I wonder if there is an element of system bias that encourages right-handedness because there aren't enough left-handed coaches/instructors so they force everyone to be right-handed for efficiency's sake.

I suppose there also may be an interesting cultural story to tell that's rooted in the indigenous Caribe cultures (e.g., left-handed people are bad luck). Certainly plenty of that mythology in the US, but maybe has more opportunity for effect there.

This culture theory should be easy to check. Just look up the players in Taiwan and Japan. My personal experience from mainland China is that conformity is highly valued. An example would be learning how to write. By extrapolation, I think Taiwan and Japan would be similar in that aspect. Do someone have those info?

My grandmother, while a natural lefty, was made to write righthanded, and this was in English boarding schools probably only 80 or so years ago. It may be that being a lefty (in general) has only come to be considered ok in the 20th century, and that that idea is only slowly filtering throughout the world.
From my years of studying Aikido, it's been drilled into our heads that "there are no lefthanded swordsmen in Japan."

My (Italian) mother used to tie my brother's left hand to force him to write righty. (Wanna guess what hand I write in?) The Italian word for "left" is "sinistre". Same in Spanish. There's definitely some cultural aspect.

However, the anomoly is MLB. The American population is 10% lefthanded. The reason you have so many lefthanded hitters is that they have the platoon advantage, with 75% RH pitchers. And the reason you have 25% LH pitchers is because there are too many LH hitters. It's just a crazy balance of power, where one side keeps trying to take advantage of the other.

I would bet that if you looked at HS or college players that the LHH and LHP numbers would be much lower than MLB.

tangotiger makes a very good point. In the pantheon of major sports, I think baseball might provide the largest incentive for acquiring left-handedness (both from a player and a team perspective). Football, basketball, soccer/football, even "lesser" sports like tennis and hockey, all seem to provide more incentive for, at best, ambidexterity. Any person, whether left- or right-handed, can acquire some measure of ability with his off-hand given enough training and practice (although generally the younger you start, the better).

I was heavily involved in contemporary wushu, the Olypmic Sport that will be introduced by China, a few years ago. Wushu literally translates as "martial arts" (which most people associate with the term "kung fu," which simply means something like "trascendent achievement through hard work"), but has evolved in the PRC into something more comparable to gymnastics. In the form competition, individual competitors perform coreographed routines inspired by the Chinese martial arts (with the acrobatic flair increased). This includes weapon forms. Unfortunately for the left-handed, all the mandatory competition forms require that one-handed weapons (e.g. swords, chain whips, rope darts, etc.) be held *with the right hand*. Pretty much the entire form is performed right-handed, with all the difficult moves done using the right hand, and only a few techniques requiring assistance from, or a switch to, the left hand. Even the more acrobatic kicks are right-leg emphasized (meaning you are expected to push off and land with the right foot).

To make a long story short, I personally know several left-handed people who came into the sport in their teens, even after high school, who developed *phenomenal* right-handed and right-legged ability. In fact, one of them got to the point where he can't do the more difficult movements with his left hand, even though that's his dominant side.

Baseball, I'm certain, has done the same thing. It's just that it promotes, rather than inhibits, switching sides. There are a multitude of examples of players who are naturally right-handed who hit from the left side, or even pitchers who switch sides because someone told them that lefties have a better chance of making it to the majors.

Left-handers naturally hit right-handed pitching better. But left-handed pitchers are generally more effective against left-handed batters. This promotes a small arms race within the sport. Although I doubt we'll ever see a time where the proportions approach 50/50.

Latin Americans are largely Catholic. Catholic schools used to strongly enforce righthandedness, and perhaps still do.

On the other side a disproportionately higher number of Canadians bat left handed. This also has a cultural explanation. Can anyone guess what it is?

I would have to guess it has to do with hockey, and how at least 2/5 of the players need to shoot left handed. The funny thing is that when I've played hockey, I've found that I'm much more comfortable with a left-handed stick, even though everything else I do is right-handed.

That's exactly right.

Recent Canadians in the majors who threw/throw with their right hand and hit with their left include (Justin Morneau, Corey Koskie, Rich Butler, Matt Stairs, Larry Walker, Rob Ducey, Doug Frobel and Terry Puhl.

The only one who threw and hit with his right hand is Jason Bay. Rob Butler threw and hit with his left hand.

And I'm sure it has to do with hockey. I do everything with my right hand (including hit) but have always shot left. I think a large proportion of kids who grow up playing hockey just naturally stick with the left side (which is not determined by handedness) when they start playing baseball. Combine this with the advantages of hitting left that were eluded to earlier and you have these somewhat surprising results.