Erin and Sara Foster Discuss ‘Nobody Wants This’ and Their ‘IVF, Baby’ Shirts

On Tuesday morning, Sara and Erin Foster, the sisters behind the Netflix series “Nobody Wants This,” joined a video call from their respective homes in Los Angeles. Sara, 43, was wearing an oversize sweatshirt, and Erin, 42, was in a bathrobe.

The sisters are known for their laid-back style, but by any standards they’ve had a busy month.

“Nobody Wants This” premiered Sept. 26, rising to the top of Netflix’s ratings within a week. The show, which is written by Erin and produced by both sisters, was inspired by Erin’s real-life love story of falling in love with her now-husband, the music executive Simon Tikhman, before converting to Judaism. In the Netflix version of the story, Joanne, a blonde, agnostic relationship podcaster played by Kristen Bell, and Noah, a bearded rabbi played by Adam Brody, navigate the various hurdles of getting into a serious relationship.

Last week, with less than a month before Election Day, the Fosters also waded into the debate over reproductive rights and in vitro fertilization. They released a limited edition T-shirt through their fashion brand, Favorite Daughter, with the bold, black words, “IVF, Baby.” (The sisters partnered with CCRM Fertility on the project. All proceeds will be donated to Resolve: the National Infertility Association.)

“They just launched like four days ago, so we haven’t had a chance to run into anyone wearing them yet, but we hope we do,” said Erin, who underwent 20 rounds of I.V.F. before welcoming a daughter in May. Sara, who has two daughters with her ex-partner, the former tennis star Tommy Haas, said sales were higher than expected.

The sisters chatted about this whirlwind time in their lives.

This interview was edited and condensed for clarity.