Martina Navratilova, considered one of the greatest female tennis players of all time, retired last week from professional tennis with yet another Grand Slam title in mixed doubles at the U.S. Open in New York City.

The victory was her 59th major championship win in a career that has spanned more than three decades. She has won 167 singles titles (18 Grand Slams) and 178 doubles titles (41 Grand Slams). Did we forget to mention she’s turning 50 next month and that she’s an out and proud lesbian?

Navratilova publicly came out of the closet in 1981 and became one of the first major sports stars to announce that she is a lesbian, ending years of speculation about her sexuality.

Although coming out earned Navratilova the respect of many, it also cost her millions of dollars in corporate sponsorship deals despite being the No. 1-ranked player from 1982 to 1986. Potential sponsors, afraid of harsh criticism from consumers and a loss of revenue if they associated their company’s name with someone openly gay, steered clear of endorsing the living tennis legend.

Billie Jean King, another out lesbian tennis legend, lost all her endorsements within 24 hours after a lawsuit by her former partner revealed she is gay in 1981.

Navratilova earned most of her millions from tournament prize money. These days, the big names in tennis don’t even have to step onto the court or pick up a racquet to earn big bucks.

Take Russian superstar Maria Sharapova, for example. Predicted to be the next dominant player after winning Wimbledon at age 17 in 2004, sponsors immediately latched onto her rising star and supermodel good looks. Sharapova signed multiyear, multimillion-dollar deals with Canon, Honda, Land Rover, TAG Heuer, Gatorade, Nike and Prince. She’s raking in the cash but has yet to even play at the same level Navratilova once did in her prime.

Before this year’s U.S. Open began, The Associated Press reported Maria Sharapova signed a lifetime endorsement deal with Prince worth $25 million during the next 10 years. It has been estimated that Sharapova earns between $23 and $25 million annually, including sponsorships and prize money. In June 2005, Forbes magazine listed her as the highest-paid female athlete in the world.

Sit down and watch TV for about 10 minutes and you’ll see the ubiquitous Nike commercial featuring Sharapova, where the Russian princess struts her stuff on the court and onlookers sing about how “pretty” she feels.

But Sharapova isn’t even the top-ranked player in the world. Out lesbian Amelie Mauresmo is, but she gets nowhere near the endorsements Sharapova receives. Mauresmo’s career prize money earnings total roughly $12 million, yet are still $8 million less than Sharapova earns in one year from endorsements alone.

According to the Bloomberg, Mauresmo, who publicly came out in 1999 when she introduced the press to her girlfriend at the Australian Open, has endorsements only with a natural gas company and eyewear retailer Alain Afflelou in France, her native country.

Mauresmo, who also has equipment sponsors with Reebok and Dunlop Sports, won her first Grand Slam title at the Australian Open this year and followed that up with a reaffirming win at Wimbledon. Did major corporate sponsors like Nike and Canon come chasing after her? No.

It’s unfortunate that Navratilova, one of the greatest athletes of all time, has been snubbed for so long and Mauresmo, an upcoming tennis legend, is still paying the price for being out.

The argument can be made that Sharapova, at 6 feet 2 inches and 130 pounds, has the model looks and charismatic personality that appeals to the masses. Mauresmo and Navratilova, who have more athletic and muscular frames, may not be considered as attractive and are thus less likely to receive lucrative sponsorships. But is that really why?

Navratilova told CNN before her speech at the Millennium March for Equality in 2000 that it’s very difficult for women to get sponsorships in general, and that it has always been a struggle. That same year, Subaru of America signed Navratilova to appear in a car advertisement, her first appearance in a national television commercial. The multimillion-dollar campaign featured three other female athletes: golfers Juli Inkster and Meg Mallon and skier Diann Roffe-Steinrotter. Was the tide finally turning?

Money can be made from our demographic. It became a priority for corporations such as Coors, Budweiser, Ford and Volkswagen.

In March 2005, Olivia, a travel and lifestyle company serving the lesbian and gay community, signed Navratilova to an endorsement deal, marking the first time a gay company has endorsed such a high-profile tennis player, as well as the first time Navratilova had been sponsored by a gay company. The endorsement was great news and a step in the right direction, but it does not compare to the pools of cash Sharapova currently swims through.