When Serena Williams steps onto Centre Court for Saturday’s Wimbledon final, it won’t simply be her 120-mph serve that sets her apart from Agnieszka Radwanska and most rivals.

Williams is the only top-10 player in women’s tennis to list a woman as her coach — in her case, mother Oracene Price shares billing with her father, Richard Williams.

Women’s tennis has blazed many trails, producing the first female athlete to top $1 million in annual prize money and many of the more prominent names and marketable faces in sports. It has also run its own professional tour for nearly 40 years, since Billie Jean King founded the Women’s Tennis Association in 1973.

But if held to standards of fair-hiring practices, it would fall short, with women markedly underrepresented in the coaching ranks.

It’s a concern of Patrick McEnroe, the U.S. Tennis Association’s general manager of player development, who hires the coaching staff that nurtures the nation’s next generation of American pros. Just two of its 24 coaches are women, and McEnroe is routinely asked by the USTA’s Board of Directors why he can’t do better.

“Obviously we make an effort,” McEnroe said, convinced female coaches relate better to young female pros. “We would love to have more.’ ”

The reasons behind the dearth are many, starting with the obvious.

Most top women players want a coach they can hit with, unless they can afford an entourage that includes a hitting partner and full-time coach.

Unlike the top men, who tend to practice with other top men, the best female players generally don’t hit with rivals, preferring to drill against a hard-slugging man.

Moreover, coaching pro players means traveling 35-40 weeks out of the year. Few women are enthused about living out of a suitcase and giving up their lives for another player’s — particularly if they’ve already spent a decade or two as a nomad during their own competitive careers.

‘It’s not all about X’s and O’s’

“It’s a lifestyle issue,” said two-time U.S. Open champion Tracy Austin, 49, who has coached promising juniors for the USTA. “I have three boys who need my attention, and I have tried to give back by coaching for three years on a part-time basis.

“The travel commitment is too demanding if you have a family.”

It’s not surprising, then, that of the handful of women who coach top players, many are mothers, as in the case of Serena and Venus Williams. Britain’s Andy Murray was coached by his mother, Judy, throughout his formative years. Four decades earlier, American Jimmy Connors learned his bruising strokes and competitive grit from his mother, Gloria.

Former pro Pam Shriver, a commentator for ESPN, isn’t convinced that enough women have been encouraged to go into tennis coaching.

“I feel like developing strong female coaches is a need,” says Shriver, a Baltimore native. “But you have to recruit. The sport needs to encourage them, because it may not happen naturally. There has to be a strategy in mind.”

Hall of Famer Martina Navratilova has experienced the barriers first-hand, told once that she wouldn’t be considered for a particular job because she hadn’t coached before.

Navratilova was struck by the irony when Murray recently hired Ivan Lendl, 52, as his coach despite the fact that Lendl hadn’t coached before. American Andy Roddick went the same route in 2006, hiring Connors in an experiment that lasted 16 months.

“How do they know I wouldn’t be a good coach?” asked Navratilova, who has won 59 Grand Slam titles in singles, doubles and mixed doubles, in a telephone interview.

“Men are kind of given more credit up front. They have to prove that they can’t coach rather than prove that they can.”

A Tennis Channel analyst, Navratilova has served as an “on-air” coach for the last six years. In addition, she notes, she was coached by some of the greatest minds in tennis — King among them.

“So unless I’m a total idiot, I should be able to pass that knowledge on,” she said.

According to several who have competed and coached at the top ranks, a coach’s gender is significant. Women can better relate to the challenges and emotions faced by female players.

“It’s not all about X’s and O’s or tactics,” said ESPN analyst and former player and coach Darren Cahill, whose charges have included Andre Agassi and Daniela Hantuchova. “It’s more about controlling those emotions, getting the best out of yourself, knowing that if you lose a great opportunity to not let that affect you for two or three games. That happens more in women’s tennis than it does in men’s tennis. And I feel like a woman’s perspective can deal with that much better.”

Eyeing healthy environment

Richard Williams readily conceded that his ex-wife “brings a lot more to the table” as a coach than he does.

“Even when we’re on the court now, I can hear Venus and Serena’s mom say something to them, and it looks like they’re paying more attention,” said the sisters’ father, who’ll be in Serena’s box Saturday, along with Oracene and male hitting partner Sasha Bajin, who has assumed day-to-day coaching duties.

He also suggests that more female coaches would create a healthier emotional environment for young players.

The issue of destructive player-coach relationships is never far from the surface of women’s tennis, though rarely discussed — whether it’s fathers who drive daughters too hard or male coaches who parlay power over their charges into sexual relationships.

“We have seen where men have brought more devastation to these young women than any woman ever would, under any circumstances,” Richard Williams said.

Added Navratilova: “We have way too many coaches that are romantically involved with the players, to their detriment.

“It may help in the short term, but it certainly will hurt them in the long term. They’re not equal relationships.

“The coach is a person of authority, and a lot of these kids aren’t 18 yet.”

In some ways, women’s tennis has been a victim of its own success.

When Stanford Coach LeLe Forood competed on the pro tour in the mid-1970s, men had so little regard for women’s tennis that few considered coaching in it. But as its credibility and popularity grew, it became an attractive, and lucrative, career path for men who weren’t ready to give up the game.

Now, it’s time for women to even the score — at least those willing to make the sacrifices required.

Forood, who has led the Cardinal to six NCAA titles, said the ranks of female coaches in college tennis are growing. Stanford graduate Laura Granville, also a former pro, was hired last month to coach Princeton’s women’s team.

And former pro Kathy Rinaldi is regarded as one of the USTA’s bright coaching stars, working with top junior American Taylor Townsend.

McEnroe wants more résumés like hers.

“It’s invaluable to be able to understand players’ highs and lows and understand the different emotions you go through as a player and a person,” McEnroe said. “It’s interesting that there don’t seem to be that many women out there who want to get into it.”