Jennifer Capriati and Serena Williams, pictured here at a tournament in 2003. Both won Grand Slam titles as teenagers.
Earlier this year, Serena Williams, 31, became the oldest woman to hold the No. 1 ranking in the history of the WTA.
Williams turned pro in 1995, just shy of her 14th birthday.
In the late 1990s, Williams battled a number of teen stars, including her sister Venus Williams and Martina Hingis. Many of the top veterans in the game were themselves former teen stars.
The Williams sisters, Jennifer Capriati, Hingis, Chris Evert, Tracy Austin and Steffi Graf all won Grand Slams before they were 20.
In the 1990s, teenagers won 15 Grand Slams. That number fell to three in the 2000s.
Today, there are no teenagers among the WTA's Top 20. In fact, there are more 30-year-olds in the Top 50 than teenagers.
What happened? Why has the teenage phenom become a rarity in women's tennis?
Jennifer Capriati with her father.
The "Jennifer Capriati Rules" are the biggest reason we see fewer teen phenoms.
These rules bar players younger than 15 from playing on the tour. Players are also restricted to a part-time schedule until they are 18.
The rules were enacted in response to off-court issues suffered by Capriati, who turned pro at age 13.
Sharapova was the last female teenager to win a Grand Slam. She was 19 when she won the 2006 U.S. Open.
Kimiko Date-Krumm at 2013 Sony Open.
Kimiko Date-Krumm is 42. She is also in ridiculous shape.
This year, Date-Krumm became the oldest woman to reach the third round at Wimbledon.
No longer content to ride off into retirement, veteran players are playing longer.
Venus Williams told ESPN "Thirty is the new 20."
Because of the age restrictions, the teen players lack experience. Meanwhile the older players, many who began as teens, have developed their games and minds.
Whatever they lack in stamina, they make up in mental toughness.
Li Na suffers an injury during 2013 Australian Open final.
The tour is longer and tougher. There are more matches on hard courts these days. The game is faster and played with more power.
The physical toll the game takes on the body requires strong inner fortitude.
There's a reason we don't see teenagers winning marathons. Prolonged stress on the body takes a toll on the psyche. Teenage girls just aren't as adept at dealing with setbacks as 30-year-old women.
The more physical style of play leads to more injuries. The mental toughness needed to work through injuries and play through pain demands a level of maturity rarely found in teens.
Actor Kevin Bacon with Maria Sharapova at 2013 Espy's awards.
Training, practice and play on the WTA tour is tough enough. Try juggling all that with television appearances, hitting the runway for charity fashion shows, pitching products and sitting for magazine interviews.
The 24/7 media blitz puts crazy demands on today's top female players.
The highest profile female athletes in the world, top tennis players, are international celebrities.
Established players like Sharapova and Williams have staffs to help manage their Facebook pages, Twitter accounts, public appearances and business ventures.
Younger players like Sloane Stephens, who suddenly find themselves in the spotlight, become overwhelmed. They pull off an upset and their Twitter followers skyrocket.
The once hungry and focused teen soon becomes more concerned with "followers" than her serve.
Serena Williams and Martina Hingis in 2001. They have 22 Grand Slam titles between them.
The days of the tennis princess are over. Top players are more like brand managers.
They have to cultivate an image while trying to maintain an audience. They sell clothing, jewelry, shoes and rackets to legions of adoring fans.
Among Forbes magazine's richest female athletes, four of the top five were professional tennis players. It's big money and big money means big business.
It takes life experience not to get caught up, chewed up and spit out.
Victoria Duval at 2013 U.S. Open.
Call it the Melanie Oudin syndrome.
Any success at a Grand Slam tournament and teen players feel the pressure to follow it up with a better showing.
Victoria Duval, 17, upset Samantha Stosur in the first round of the U.S. Open. In the second round, Duval did what most inexperienced qualifiers do when facing a veteran player like Daniela Hantuchova: She lost.
But that didn't stop commentators and fans from speaking about Duval as "the next big thing."
There is so much pressure on teens these days. They are not allowed to develop without being overly scrutinized. The natural process of paying dues is interrupted by unreasonable expectations.
In 1981, Kathy Rinaldi won a match at Wimbledon at age 14. She was quickly labeled the next Chris Evert.
She wasn't. However, Rinaldi went on to have a solid career. She reached as high as No. 7 and played in a couple of Grand Slam semifinals.
That was before the internet, Twitter and TMZ. She didn't have to read endless blogs about her slumps. Twitter didn't broadcast all her missteps.
Rinaldi now coaches teens, including Taylor Townsend. Rinaldi told the SunSentinel the age restrictions delay a player's progress until they are in their 20s.
With no apparent plans to remove the restrictions, and older players showing no signs of easing up, we may see a 35-year-old win a Grand Slam before another teen does.