NEW YORK -- Melanie Oudin might be the freshest face to come along in U.S. women's tennis in a decade, but she's also a throwback.
Throughout the '70s, '80s and '90s, American fans grew accustomed to watching teen angels wing their way onto the scene every few years, from Chris Evert to Tracy Austin to Andrea Jaeger to Jennifer Capriati, all of whom were winning professional tournaments or making a splash in the majors before they turned 17.
The rest of the world contributed similarly early-blooming stars such as Martina Navratilova, Steffi Graf, Monica Seles and Martina Hingis in the same period. Their precociousness, pluck and ponytails made for irresistible storylines and fan loyalty that would persist well after the girls grew up.
Youthful champions seemed as prevalent as ever in the late '90s. A 16-year-old Hingis became the youngest-ever Slam champion when she won the Australian Open in 1997 and the youngest-ever WTA No. 1 shortly thereafter. Hingis reached the final of all four majors that year, losing to 19-year-old Iva Majoli at Roland Garros and defeating 17-year-old Venus Williams at the U.S. Open. In 1999, Hingis won her third straight Australian title at 18 and Venus' sister Serena captured the U.S. Open a couple of weeks before her 18th birthday.
Then the tide slowed to a trickle. Just three Grand Slam titles have been won by teenagers in the past 10 years: Maria Sharapova, who was 17 when she lifted the trophy at Wimbledon in 2004 and 19 when she won the 2006 U.S. Open; and fellow Russian Svetlana Kuznetsova, a U.S. Open champion at 19 in 2004. All-teen matchups deep in majors -- such as Oudin's Wednesday quarterfinals showdown against ninth-seeded Caroline Wozniacki, 19, of Denmark -- have become increasingly rare.
Part of the shift has to do with increased power in the game, which makes physical maturity not just an asset but a near requirement for success. However, there's no doubt that the WTA's age eligibility rules -- instituted in 1995 and revised 10 years later -- have made it less likely that teenagers will rocket into tennis consciousness as if shot from a cannon.
Part of the idea behind those rules is to prevent an adolescent player from being scorched on her upward trajectory. They came into being chiefly because of the corporate soul-searching that followed Capriati's downward personal spiral after spending her formative years in the sport's high beams. With that episode and others came the conviction that the youngest athletes needed to be protected not only physically but also psychologically from overwork and possible exploitation.
Current WTA rules don't allow girls under 13 to play in professional tournaments. At 14, they can enter eight events on the lower-level International Tennis Federation circuit and accept one wild card to a WTA event. With each additional year of age, the number of allowable professional tournaments increases: 10 events at age 15, 12 events at age 16, 16 events at age 17. A player in the 15-17 age range can participate in Fed Cup if selected, and in the year-end championship tournaments if she qualifies. At 18, the walls come down.
The tour also requires teenage players to enroll in a program called Pro U, in which they receive guidance on everything from managing their careers to dealing with the media.
There is some flexibility in the regulations for players whose progress is exceptional. If their ranking is high enough to get into the main draw or qualifying rounds of certain tournaments -- Grand Slams and "premier" events that include Indian Wells, Miami, Madrid and Beijing -- playing in those events doesn't count against their yearly quota.
The ATP also has eligibility rules, but they don't often come into play because younger teenage boys are seldom physically mature enough to pit themselves against older men. Boys under 14 are not allowed to play pro events. They are permitted to play in a maximum of eight ATP or Challenger-level events after turning 14, and a maximum of 12 when they turn 15. At 16, no restrictions apply.
John Tobias, president of the BEST management company's tennis division and Wozniacki's agent, said that ideally young athletes would be evaluated on a case-by-case basis but that he realizes that's not practical. He said there are other ways of giving teenagers more match experience when their pro events are limited, such as World Team Tennis competition and exhibitions. "Overall, I think [age eligibility rules] are not a bad idea," Tobias said. "They can actually prolong careers."
Would there be a few more Oudins popping up if those regulations weren't in place? Perhaps. Oudin's mother, Leslie, said she wishes her daughter could have entered more professional events "a little bit earlier, to gauge her abilities against some of these players."
The 15- to 17-year-olds spend those seasons bouncing among junior tournaments, ITF and WTA events -- three very different levels of competition in venues that range from the most grandiose to the most humble. Scheduling can be tricky, and the back-and-forth might induce the competitive bends.
Former top-10 player Chanda Rubin turned pro at 15 in 1991, before the eligibility rules were in place. The Louisiana native stopped playing in junior events the year she turned 16, when she found herself in a classic in-between stage: She lost to Capriati in the first round of Wimbledon, then won the junior Wimbledon championship the next week. Yet Rubin didn't play a full professional schedule for a couple of years, "not because it was dictated, but because I was still going to school and education was important to me and my parents."
Rubin said she's glad she had the freedom to tailor her early career to her maturity and individual needs. "I definitely felt that the initial hard line [spelled out by WTA age eligibility rules] was based on one case and it didn't need to be such a hard line," she said. "That was a special case with variables we aren't going to see, maybe ever again."
But she added that she doesn't think the rules seriously impair a player's professional development. "The bottom line is that if you're able to compete at that level, you will, even if you can only play a handful of tournaments," Rubin said.
Many agree that the intended tradeoff -- a longer career and healthier physique and psyche -- is worth it.
"I understand the principle behind it, and I think it's a good rule," said agent Ben Crandell, whose IMG clients include 16-year-old Michelle Larcher de Brito, a third-year pro. "Because of it, it might take players a little longer to reach their potential, and a story like Melanie's at the U.S. Open doesn't happen as often as it might.
"Every player's different. Some need it more than others."
ESPN analyst Patrick McEnroe, the U.S. Tennis Association's manager for elite player development, said he thinks the rules could use a little more wiggle room to accommodate players who are ready.
"Not to go back to a free-for-all, the way it was," McEnroe said. "But I have felt in the last five to seven years that it's more difficult for younger players to break through. The best women players are peaking later. Melanie has bucked that trend just by getting to the quarters.
"We like to see a progression. Don't play more professional events until you've proved yourself at the junior level. Don't skip steps."
Bonnie D. Ford covers tennis and Olympic sports for ESPN.com. She can be reached at firstname.lastname@example.org.