The format evokes Japan’s most popular romantic reality show, “Terrace House,” with its assembly of clean cut and exceedingly polite cast members, overseen by a panel of jovial commentators.

Cast members were not advised against speaking about the social challenges of being gay or bisexual in Japan, he said, but during the audition process, he reminded prospective participants that “ultimately it will be streamed, and a wide range of viewers will be able to hear those thoughts.”

The shadow of “Terrace House” inevitably hangs over “The Boyfriend.” They share the same basic format and one of the commentators — Yoshimi Tokui — has returned to the studio where he and a slate of television personalities dissect the interactions between the men on the show.

Her mother, Kyoko Kimura, has filed a lawsuit against Fuji TV and two other production companies, accusing them of failing to protect her daughter from slanderous comments and forcing her to behave on the show in a way that attracted mass criticism online.

Although polls show that more than 70 percent of the Japanese public supports legalizing same-sex unions, gay and transgender people are still subject to discrimination and hate speech.

Ms. Kimura, 47, said in a video interview that she knew from her daughter’s experience that young people new to international exposure “can’t imagine what it would be like to actually receive hundreds or thousands of slanderous comments from all over the world a day.”

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