Equal pay for equal work!
Except, one plays best of 3 in majors and the other plays best of 5
Sigh....... google is your best friend:
"The short answer is: They tried! The players and the WTA themselves have offered repeatedly. But the tournaments said no, partly for historical reasons rooted in sexism.
Firstly, the obvious point: female tennis players are more-than-fit enough to play best-of-5s given the typical day of rest that Grand Slams schedules offer. To add in some logic and science:
The world has very few sports for female athletes that pay enough to have deep talent pools; tennis is perhaps the best career option for an aspiring female professional athlete. As Venus put it, tennis is "the world's leading sport for women". The top 100 women's tennis players are consequently, I would argue, bigger outliers on the bell curve for female athletics than the men's players are relative to male pro athletes - who often opt for better-paid team sports when they can.
Women being physically smaller gives them an advantage in tolerating hot and humid conditions (see e.g. this study of runners, or this one)
Women burn more fat and less carbohydrate during endurance exercise, meaning in long athletic contests, their muscle glycogen will outlast that of men (study #1, study #2, study #3)
Estrogen protects muscles from exercise-induced damage (study)
See also from Quora: What are the biological advantages of being a girl?
Males have meaningfully higher VO2Max levels, meaning they can play harder while exercising, but there's no reason women can't play just as long. I mean, Caroline Wozniacki trained for and ran the 2014 NY Marathon, for charity, in the middle of a year on the WTA circuit (where she was ranked 8th at race time). Let me know next time Rafael Nadal goes out of his way to put 26 more miles on his knees.
Secondly, there's some history of women playing best-of-5:
Women played best-of-5 in the championship match of the WTA Tour Finals (effectively the year's 5th major) from 1984 to 1998, with 3 epic 5-setters, including a legendary 1990 final where Monica Seles came back from a 2-1 deficit to win in 5, meaning she would have lost the title under a best-of-3. Seles later wrote in her memoirs that it was the only chance of the year where she could "play like a man".
The best-of-5 format was a hit with the women, with 1990 runner-up Anke Huber saying "everybody among the women can do it"
In the predecessor to the US Open, the ladies' championship match was best-of-5 from 1891 to 1901 (U.S. Open Women's Finals Results)
And in the most famous example, Billie Jean King's Battle of the Sexes vs Bobby Riggs in 1973, was also best-of-5. Was the whole concept theatrical? Yes. Farcical? Arguably. But still, nobody fainted at the suggestion, certainly not King, who was Queen on that day.
Thirdly, top players and the tour itself have frequently asked to play best-of-5s in the Grand Slams (both the women's and men's tour play best-of-3 the entire rest of the tour calendar, with rare exceptions for some Finals matches):
Stacey Allaster, until recently the head of the WTA (women's tour), says her women are 'ready, willing and able' to play five sets, and just notes the scheduling difficulties that have prevented adoption. She has said this repeatedly.
... as has Billie Jean King, founder of the WTA.
Andy Murray said in 2013 that 'Women should play best-of-five sets', and notes the history to add "it's not like women cannot play 5 sets".
Martina Navratilova, arguably the best player of all time, has often advocated for playing best-of-5: "Weíve been saying for years, years, that we want to play five sets, but they always said: ĎOh, no, no, we want it to stay the way it is.í ". Although, she has more recently been quoted as saying the men's tour ought to revert to best-of-3 instead.
Serena Williams, also arguably the best player of all time, likewise notes that the Player's Council (which she is on) has offered to play best-of-5 "many, many, many occasions, but itís not what the tournaments, in general, desire". She's repeated this when just speaking for herself, as well, sometimes in cocky fashion.
Venus Williams and Angelique Kerber have also expressed support for the idea, though Petra Kvitova says she'd need to work on her stamina more.
So there's no lack of interest by the players. Not to mention, figures on the Men's tour have occasionally debated the merits of going back to a best-of-3 format, to lessen injuries. Figures in the sports media have sometimes suggested women should play five-set matches, too.
Finally, however, it's not up to the WTA or its players. The Grand Slams are run by the ITF (International Tennis Federation), the world governing body for the sport, based in London. The ITF also organizes the lower-level tournaments - for both genders - that serve as the sport's minor leagues. And despite the protestations from the WTA and the women's Player's Council, the ITF's Grand Slam Committee has resisted calls to let women play best-of-5 in the grand slams.
David Brewer, head of the US Open (and a member of that committee), said last year that it's "news to [him]" that the women want to play best-of-5.
Women have offered to play best-of-5 since the equal-pay issue started becoming a question in the early 90s, but as Pam Shriver said of the WTA's offer, the ITF "either didn't take it seriously or they dismissed it."
The ITF's Grand Slam Committee is often very concerned about scheduling around rainouts and TV coverage, and this is the typical excuse given for why the ITF won't let women play best-of-5."