Turning 40 is a significant birthday for anyone in any profession, but especially for athletes. By then, most tennis players are long retired. But Venus Williams, who turns 40 in June, is still very much on the scene. Twenty years after winning her first Grand Slam singles title at the 2000 Wimbledon Championships, and after almost a decade of dealing with the autoimmune disorder Sjögren’s syndrome, she still appears to love playing tennis as much as ever. Currently on 49 career singles titles, Venus could bring up her half-century in 2020.
It's 40 years since a mother last won Wimbledon, going back to Evonne Goolagong's triumph at the 1980 Championships. But with Kim Clijsters returning to the WTA Tour, joining other high-profile mothers such as Serena Williams and Victoria Azarenka, perhaps 2020 will see a mom attending the Champions' Dinner.
Will Bianca Andreescu, the 19-year-old winner of the 2019 US Open, go on to become the first teenage champion at the Australian Open this millennium?
It's 50 years since Margaret Court achieved the calendar-year Grand Slam by sweeping the four majors in 1970. Perhaps 2020 might also be the year when Serena Williams, who has uncharacteristically lost her last four Grand Slam finals, equals the Australian's all-time record of 24 major singles titles.
It's also 50 years since the Original Nine took a stand against unequal pay in tennis - and set up a tour of their own. Women's tennis owes a great debt to Billie Jean King, Rosie Casals, Nancy Richey, Julie Heldman, Valerie Ziegenfuss, Judy Dalton, Kerry Melville Reid, Peaches Bartkowicz, and Kristy Pigeon.
Will Venus or Serena Williams win a record-extending fifth gold medal at the Olympics? Or perhaps they might win one together in the doubles at the Tokyo Games. The sisters are already the only women to have landed four gold medals. They have won the singles once each, and the doubles on three occasions.
In the summer of 2020, Martina Navratilova will be celebrating the 30th anniversary of taking the 1990 Wimbledon title for what was her ninth singles title at the All England Club. That number is still unmatched in the women's or men's games, though Roger Federer came extremely close in the 2019 final against Novak Djokovic, holding two championship points for what would have been a ninth title.
Thirty years ago, a 16-year-old Monica Seles defeated Stefanie Graf in the 1990 French Open final to become the tournament's youngest ever champion. That record still stands.
Will Ashleigh Barty win her home Grand Slam to become the first Australian women's singles champion at the Australian Open since Chris O'Neill in 1978?
Will a 38-year-old Serena Williams extend her own record as the oldest Grand Slam singles champion in history? Williams already has that distinction, on account of winning the 2017 Australian Open at the age of 35.
Will Barty become only the fourth woman this millennium to snaffle successive titles at the season finale? Barty, who won the 2019 Shiseido WTA Finals Shenzhen, would join Kim Clijsters, Justine Henin and Serena Williams.