Who is going to win the women’s singles title at the French Open? Maybe Simona Halep, who is ranked No. 1 but has yet to win a major. Or Garbiñe Muguruza, who won the title in 2016. Or 36-year-old Serena Williams, who had played just four singles matches since she won the Australian Open last year while eight weeks pregnant. (She won in the first round Tuesday.) Petra Kvitova, a two-time Wimbledon champion, looks good right now. So does Kiki Bertens, a 26-year-old who has never reached a Grand Slam final. Maria Sharapova is still around. Elina Svitolina, ranked No. 4, recently won the Italian Open and looks in top form. Or maybe a young and upcoming woman like Katerina Siniakova, age 22. Or better still, another player no one has heard anything about and isn’t expected to win under any circumstances.

That last scenario might seem improbable until you recall that it happened at the French Open last year, when 20-year-old Jelena Ostapenko took the title despite having never won more than two matches in a Grand Slam tournament before. Ostapenko’s win followed a recent trend of surprise winners: Since Williams took her leave from the sport, three of the four majors were won by a player with no previous Slam titles.

Williams’s absence is certainly a big part of that. But since 1990, the battles at the top of women’s tennis have become less predictable. In the 1980s, the best destroyed the rest. Martina Navratilova and Chris Evert ramped up their rivalry and dominated their competition before the remarkable Steffi Graf came along. Other than Graf, only three players won their first Slam in the ’80s. Even more unusual: Only 11 women reached a Grand Slam final for the first time.

First-time women’s Grand Slam winners and finalists, by decade First-time … Decade Finalists Winners 2010s 21 11 2000s 12 9 1990s 13 9 1980s 11 4 1970s 20 8 Source: ESPN Stats & Information Group

Since then, though, dominance has been declining. The 1990s and 2000s had more debut Slam winners and more first-time finalists. And remember, both of those decades included Williams and her sister, Venus. They’ve both played well since 2010, too, with Serena winning 12 major titles. (That’s more than half of her total of 23 and one behind Margaret Court’s all-time record of 24.)

Yet despite Serena’s talent, many other women have found ways to reach major finals and, often, win them. Australian Samantha Stosur made it to the French final in 2010 before beating Serena in the 2011 U.S. Open final. Williams looked like she might win all four majors in 2015, but she lost in the U.S. Open semifinals to Roberta Vinci, who had never reached a Grand Slam final before. Vinci’s opponent in that final, Flavia Pennetta, won her first — and last — major: She announced her retirement shortly after capturing the title. In this current stretch from 2010, seven women have now won their first major and have not yet won a second.

Last year, Venus Williams was the only player who made more than one final (losing to her sister in Melbourne and to Muguruza at Wimbledon). And in 2014, as Serena was starting her run of Slams and Venus was on the comeback trail, the four Grand Slams had eight unique finalists.

Men’s tennis at the moment couldn’t be more different. Since Rafael Nadal won his first major at the 2005 French Open, five men have won 50 Grand Slam titles (Nadal, Roger Federer, Novak Djokovic, Andy Murray, and Stan Wawrinka). Juan Martin del Potro and Marin Cilic won the other two Slams in that period, and they had to beat one of the five dominant men of the era to take the title. (Del Potro beat Nadal in the semifinal and Federer in the final at the 2009 U.S. Open, while Cilic thumped Federer in the 2014 U.S. Open semifinals.)

The question for the women: Will another player take over the game, like Serena Williams, Graf, Navratilova, Evert and others have done before? All signs point to no, because there’s too much talent from too many countries, and too much power, speed and stamina required to win a Slam. Still, it’s unpredictable. Just look at the men: In 2002, Pete Sampras won his 14th major title at the U.S. Open, the last tournament of his career. At the time, everyone thought that record would last for ages — until Federer and Nadal came along and both passed it, and both might add still more to their totals. In tennis, the only thing we know for sure is that anything can happen, especially when you least expect it.

CORRECTION (May 30, 2018, 2:45 p.m.): A photo of Karolina Pliskova in an earlier version of this article was incorrectly identified as Elina Svitolina.