Forget performance-enhancing drugs, Major League Baseball's biggest problem may be that its audience keeps getting older.

Nationally, MLB regular-season viewers are continuing to get older with the 55-plus audience comprising 50% of all viewers, versus 41% 10 seasons ago, according to Nielsen's 2013 Year In Sports Media Report. With another 26% of its viewers are 35 to 54, which leaves baseball with only 24% of its fanbase under 35.

On the plus side, baseball's aging, 70% male, 83% white audience (according to Nielsen) appears desirable to its TV partners. MLB's eight-year national media rights agreements with Fox (NASDAQ:FOX) and Time Warner's (NYSE: TWX) TBS, combined with the league's deal with Disney's (NYSE:DIS) ESPN, brings in $12.4 billion.

But if new fans don't watch the sport, how long will it be before its aging audience makes baseball a much-less desirable property?

Kids just aren't watching Major League Baseball
The average World Series viewer in 2013 was 54.4 years old, according to Nielsen.That's up from 49.9 in 2009. Kids age 6 to 17 represented just 4.3% of the average audience for the American and National League Championship Series this year, compared with 7.4% a decade ago, The Wall Street Journal reported.

"Kids make up a larger segment of the television audiences for the NBA, NHL, and even soccer's English Premier League than they do for baseball," the same article reported. Ignoring the NFL -- which dwarfs all sports in all age groups -- The Journal wrote that kids accounted for 9.4% of the NBA conference finals audience in 2013, while the NHL's conference finals drew 9%, and Premier League soccer pulls in 11%.

"I think we're at an obvious crossroads," Red Sox president Larry Lucchino told Sports Illustrated. "The aging and graying of baseball's demographics is obviously a concern and has been for several years, but the opportunity it presents is interesting."

Kids just aren't playing Little League
Whether it's the growth of "extreme" sports, more kids playing other sports, or a byproduct of parents who don't watch baseball -- fewer kids are playing the sport.
From 2000 to 2009, the latest years for which figures are available, the number of kids aged 7 to 17 playing baseball fell 24%, according to the National Sporting Goods Association, as reported by The Wall Street Journal. Youth tackle football has climbed 21% over the same time span, while ice hockey jumped 38%. The Sporting Goods Manufacturing Association said baseball participation fell 12.7% for the overall population.

"The days of kids being born with a glove next to their ear in the crib and boys playing catch in the backyard by age three, those are over," Len Coleman, the former National League president told The Journal.
If less kids play baseball, those kids grow into adults who don't appreciate the intricacies of the game. Lots of kids playing does not always equal TV ratings (soccer being the obvious example), but if kids stop playing baseball, it's hard to imagine they will watch it as they get older.
Can Major League Baseball fix it?
To draw in younger viewers, baseball has to find ways to appeal to the younger generation and air games at times they can watch and attend. One way to start accomplishing that goal would be to speed up the pace of the game. As The Washington Post reported last season, "Forty years ago, the average major league game lasted about 2.5 hours. By 2002, that ballooned to 2:52. Last year, the average game was 2:55. Midway through this season, games have lasted an average of 2:57."

Speeding up the game could be done by adding a pitch clock to force pitchers to play quicker. MLB could limit the number of trips to the mound managers and position players can make. The league could also eliminate warm-up pitches, except in the case of an injury.

Attracting younger fans also requires that baseball do something that hurts in the short term, but could pay off down the road -- lower ticket prices and have more day games. The Fan Cost Index  -- the price for four adult average-price tickets, two small draft beers, four small soft drinks, four regular-size hot dogs, parking for one car, two game programs, and two least-expensive, adult-size adjustable caps -- ranged from $336.99 for the Boston Red Sox to $151.55 for the Arizona Diamonbacks, according to KSHB 41 in Kansas City.

Watching a game on a sunny day with a hot dog and an age-appropriate beverage is one of the easiest ways for young people to discover baseball. But with high prices and late start times, the in-stadium experience is impossible for many families.

The bottom line
If baseball doesn't find younger fans, it's going to be a quaint memory -- like the accordion and milk men. Fortunately, MLB is performing well with rising revenue and a well-off fanbase. But it's hard to be considered the National Pastime if you can't get younger fans into your park.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.