Japanese ultrarunner Tomomi Bitoh is a doer.

When she made the choice to freeze her eggs so she could become pregnant once she’s ready, she did it without thinking twice. In November 2023, a month before her 33rd birthday, she headed straight to a Tokyo clinic from the airport after completing a 170-kilometer high-altitude trail running race in the Himalayas.

“I didn’t ask anyone for their opinion. I didn’t even tell my parents. I’ve always known what I wanted for myself,” Bitoh, now 34, said. “I want to have a baby one day. Just not now.”