Somewhere on this planet, two people are getting ready for the biggest trip of their lives: a weeklong, scenic loop around the moon.

On Monday, Elon Musk announced that his company SpaceX would send two space tourists on the journey next year, but said little about who they were. They’re not astronauts, they asked SpaceX to take them, they’re paying a lot of money for it, and “it’s nobody from Hollywood.” He wouldn’t even give their genders.

And this is where it gets interesting. Only 24 people, all Americans, have flown to the moon, and 12 of them have walked on its surface. They had one important thing in common: they were all men.

If even one of those mystery passengers is a woman, SpaceX would be making history.

Americans have not sent anyone to the moon in 45 years. To make a triumphant return with two dudes on board would make that return seem, well, less triumphant.

While the Apollo program was launching man after man into orbit in the 1960s and 1970s, a women’s rights movement swept more women than ever before into the workforce, including into the sciences, engineering, and other fields that contribute to human space exploration. In the last decade or so, the number of aerospace engineers inside NASA rose by 76 percent. And yet, many women in these male-dominated fields continue to be overlooked and underpaid. But times have changed in one respect. The idea of a female astronaut, considered by many to be ridiculous during the Apollo era, is now anything but.

Musk said the individuals approached SpaceX, so the company likely couldn’t dictate the gender breakdown of the trip, especially with bags of money on the table. But they should be aware of the optics that would come with a two-man trip set against a backdrop of visible achievements by women in science, imagined or real. The American public has watched Sandra Bullock hurtle from space to Earth in one piece in Gravity and Amy Adams learn to talk to aliens in Arrival. They’ve read about Kate Rubins sequencing DNA on the International Space Station for the first time in history, and heard the real-life stories of Katherine Johnson, Dorothy Vaughan, and Mary Jackson in Hidden Figures.

“Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration,” the company said of the trip. Surely “humankind” must include a representative of half of the world’s population. When reached for comment Tuesday, SpaceX declined to comment on the genders of the passengers.

Americans got a late start to sending women to space, for all the reasons one would expect: exploring the cosmos—like serving in the military, running a company, and otherwise bringing home the bacon—was considered man’s work. In 1962, John Glenn, a few months after he became the first American to orbit the Earth, appeared at a congressional committee about the possibility of training female astronauts and said women can’t do what he did.

“The men go off and fight the wars and fly the airplanes and come back and help design and build and test them,” he said. “The fact that women are not in this field is a fact of our social order.” Sally Ride, the first American woman in space, flew aboard the space shuttle in 1983, a full 20 years after the Russians sent Valentina Tereshkova on a Vostok mission to orbit the Earth. The U.S. soon outpaced the Russians, and have now sent nearly 60 women to space compared to Russia’s measly four. Female astronauts may face the same challenges that female employees face in workplaces elsewhere, but at least NASA is no longer—I hope—asking them, as they asked Ride back in 1983, whether 100 tampons would be enough for a weeklong mission.