While soccer fans the world over were glued to the World Cup last week, there is another time-honored sporting tradition going on -- Wimbledon. Billie Jean King won a record 20 Wimbledon titles and 71 singles titles over the course of her career. Many of us also remember her for her victory against Bobby Riggs in the 1973 Battle of the Sexes. Her accomplishments on and off the court explain why Life magazine named her one of the 100 Most Important Americans of the 20th Century.  Today she is co-founder and majority owner of the World Team Tennis League. She joined David and Tom Gardner on The Motley Fool Radio Show from Wimbledon, England.

TMF: Billie Jean King, welcome to The Motley Fool Radio Show.

Billie Jean King: Hey! Thanks a lot, Tom and Dave. It is good to talk to you. 

TMF: We wanted to start by asking you about something that you are currently the majority owner of, the World Team Tennis Pro League, which includes players like Andre Agassi, Lindsay Davenport. Is it a good business to be in or do you think of it as more of a passion?

Billie Jean King: I think of it as both. I like putting money back into what made my life and tennis has been great to me. Obviously I love team sports. I grew up in a family of team sports. My younger brother Randy Moffitt was a professional baseball player most of his career with the San Francisco Giants as a relief pitcher. So I always grew up around team sports and I always wanted to help make tennis a team sport. I always liked co-ed events best so we have two men and two women on each team and my dream is for someday that the World Team Tennis format is in the Olympics as our team sport for tennis.

TMF: Billie Jean, you were the first woman to win more than $100,000 in a single season in any sport. Today's players, as you mentioned, compete for prize money that is usually a little bit north of $100,000 just for one tournament. So I guess my question is, does Billie Jean King ever wish she were born just a few years later?

Billie Jean King: Yes, I would love to be a player today. I had the right personality for it. I love it. I love to promote our sport. I love grass-roots tennis. I love coaching. I love all parts of the sport plus as you know, I love the business side. 

A lot of you don't realize that I was always in the tennis business, like I have told you earlier, from 1968.  I was in tournaments and also on World Team Tennis teams as well. So today if I were around I would be in hog heaven, but I also get a lot of gratification on what we all did to change the landscape and climate of our sport. 

TMF: When you look at tennis today, what are the biggest differences between the business of women's tennis and the business of men's tennis?

Billie Jean King: Men still get a lot more opportunity. It is still a big part of the "old boy" network. They have many more companies they can go to and get money from. They can have a huge turnover of sponsorship and still survive I think a lot better than the women. But the women's ratings are better, at least at home in the United States than in the men's tennis. 

Women's sports is still in its infancy. Really, the beginning of women's sports for us in the United States started in 1972 with the passage of Title 9 for girls to finally get athletic scholarships for the first time. So a girl didn't get an athletic scholarship until the fall of 1972 for the very first time. 

TMF: OK. Let's talk about an event that is forever etched in many of our memories: your victory over Bobby Riggs in the 1973 Battle of the Sexes at the Houston Astrodome. When you describe that event to someone born after 1973, what do you say to them?

Billie Jean King: I try to set the scene for them. I try to tell them that Watergate was heating up. That it was the height of the Women's Movement. In 1973, a woman could not get a credit card without her husband or father or a male signing off on it. So I think that puts it pretty much in perspective because I think most young people today cannot imagine, a boy or a girl, without a credit card.

TMF: We were talking to our producer, Mac Greer, earlier. He was nine at the time, and he actually went to your match with his entire family. Mac was saying he was admitting to rooting for Bobby Riggs, but says that he was under duress from the men in his family. He wanted us to pass along his sincere apologies some 29 years later. (Laughs)

Billie Jean King: (Laughing) It is interesting because that is very typical. Mac is what I call the first generation of men of the Women's Movement. His generation, Mac's generation, in their late 30s or 40s now, is the first generation of men of the Women's Movement, and they are the first generation of men that insist that their daughters and sons have equal opportunities. 

That match was very significant in that it symbolized exactly what was transpiring, and it was so visual and impactful. I have people every single day since that match come up to me, and the men, if they are in their 30s and 40s, tell me how that changed their lives, and now that they have daughters or if they have both daughters and sons, tell me they have a very different feel about how they want their daughters to be treated because of seeing that match.

TMF: What a great memory.

TMF: When we talk gender equality in and out of sports, how much do you think things have changed since 1973?

Billie Jean King: Well, I can tell you in 1973, women got 59 cents on the dollar; now we are getting 74 cents on the dollar. In the area of finance and business, we are at 68 cents on the dollar.  That is where the power, opportunity, and choice come from -- when you have money. Money equals opportunity. There is no question. Women of color today are making 59 cents, just like the Caucasian women were making in 1973, so they are 30 years behind right now, the women of color. 

We have a long way to go and it is really in the area of business. The "old boy" network is still very strong and very true. Just look at the stock exchange and how many men and women are in there. You look at all these areas, and it is still very much run by men. 

Sports are a microcosm of society, and I think if you look at the '90s in women's sports, for instance, of course it is a very small sector, but you can see where the reason the women in 1996 won all these Olympic golds, the American women, was because of Title 9. It was like 25 years from the time that it was passed in '72. We won the gold in basketball, soccer, softball, and rhythmic gymnastics. I have probably forgotten another one, but those four for sure off the top of my head. That is just a reflection of how women are finally having more choices and doing their thing.

As far as the business, I know that when they take surveys of women in business, of the top 500, Fortune 500, the successful women, 80% say they definitely were in sports as a young woman.... It teaches you character, it teaches you to play by the rules, it teaches you to know what it feels like to win and lose, and it teaches you about life. It is lessons in life that you have to hang in there when things are tough as well. With the stock market the way it is right now, we have to be patient. 

I come from a family that is very conservative. They always paid their bills. If they didn't have the money, we didn't get it. So what I do in my business, I have my Rock Money I am not allowed to touch, and then I have my Fun Mon that I go into more of a high-risk area if I want. To have fun and sometimes I just know that can be a big, fat zero. 

TMF: If we look back on your career, what would you highlight as your smartest and your dumbest investment?

Billie Jean King: (Laughs) Dumbest investments are the dot-com's, but I knew it was a dumb investment and I didn't care. I like entrepreneurial people; I like people who take risk. I know that is where I take my Fun Mon and I put it in and if I get lucky, one out of 100, great. If I don't so be it. If I can hit a couple of singles and maybe one home run in a lifetime, great. But my smartest one as far as the most fun has been my World Team Tennis, you know, my putting money back into our business has been the right thing to do. I want to put money back into tennis because it has been so good to me.

TMF: You are someone who loves games and you are someone who loves sports, and so we close with our own game. We call it "Buy, Sell or Hold?" We are going to present you with a theme, a person, something going on in society and we ask you, if it were a stock, would you be buying, selling, or holding now, and give us one sentence as to why. Are you ready to play?

Billie Jean King: I am playing.

TMF:  OK. Buy sell or hold: John McEnroe's new autobiography, You Can't Be Serious.

Billie Jean King: Aaah, you have got to buy it. 

TMF: Do you think Tatum O'Neal will?

Billie Jean King: Tatum just helped him sell books because she got on 20/20 and started trashing him a little, I think, inappropriately. The irony of the whole thing is it is probably going to sell more books for John McEnroe. 

TMF: That is probably true. Now we can hear the Wimbledon cheers behind you so that is appropriate for me to ask you the next one. Buy, sell, or hold the likelihood of a Billie Jean King comeback?

Billie Jean King: (Laughs)

TMF: Come on now.

Billie Jean King: (Laughing) Hold baby! Hold! Hold!

TMF: So it is at least a hold. At least a hold. (Laughs)

Billie Jean King: Yeah, maybe. (Laughing)

TMF:  Finally, many people may not know that Elton John wrote this song for you. Buy, sell, or hold the song, "Philadelphia Freedom"?

Billie Jean King: Oh baby, buy, buy, buy! 

TMF: Billie Jean King, thanks for joining us on The Motley Fool Radio Show.

Billie Jean King: Thanks so much, Tom and Dave. 

("Philadelphia Freedom" music playing in background)

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