That which seems the height of absurdity in one generation often becomes the height of wisdom in the next.
—John Stuart "Brad" Mill

The lotus' stem is as long as the depth of water,
So men's height is just as great as their inner strength.
—Tiruvalluvar

While I'm droning on the subject of height, I thought I would answer this question from a previous post's comments:

rbj

Are ballplayers getting taller relative to the general population trend of increasing height? And if so, is it due to better nutrition (or other legal/illegal substances) or are teams more interested in taller people as pitchers?

Well, I didn't have the general population data, but was able to get something close here. It's a report with data dating back to 1960 from the CDC.

First, I got a baseline of for the average height per decade. A notes on how I derived this data: I ignored players for which there was no data. I averaged based on player years in a given decade, meaning that a player who was active for four seasons in, say, the 1990s counts for four entries in the internal table used to derive the average. Basically, it's weighted by years active. I believe this gives a better representation of the average player in a given year for the concerned decade.

Next, I split up the players by position players and pitchers. Then I found the ratio for pitcher height to position player height. (For the record, the only year that the average position player was taller than the average pitcher was 1878.) And for each category I looked at the percent change each decade.

OK, enough of my yakking, let's boogie…

You may notice that the only two times that the average pitcher shrank was right before the two biggest offensive explosions in major-league history (the Twenties and the Nineties). Maybe the fact that the taller and usually better athlete was looking toward offense and not pitching might have more to do with the explosions than steroids (especially since steroids were hard to come by in the era of prohibition, though reportedly, Joe Kennedy could lay his hands on 'em).

Also, pitchers have consistently been slightly taller since the dawn of major-league baseball. Other than a slight spike in the early part of the twentieth century, the pitchers have become ever so slightly taller as compared to position players extremely gradually throughout baseball history.

Anyway, back to the general population. Here's a comparison between the average player and the average American male for the decades available:

So the answer to the original question is no. Players are not growing faster than the average American. If anything, it's the reverse.

I think it goes back to what I found in the last study, that height has absolutely no correlation to how well a player (actually, it was at the team level) does on the field. There's a tangential study on player pool depth that would address this. I have just such a study that I designed a while back, but was part of my competitive balance series that is currently on hiatus. They'll more on this later—maybe I'll save it for the long lockout that will come after the All-Star game.