Across the country, many Americans have commemorated the 10th anniversary of the Supreme Court’s decision guaranteeing same-sex couples the right to marry nationwide. They have pointed to the broad social acceptance for same-sex marriage and vowed to fend off legal threats to the landmark ruling.

But for some veterans of the marriage equality movement, celebration was muted by another Supreme Court ruling a week earlier in which the right for states to ban some gender-transition medical treatments for young people was upheld. It is an area of L.G.B.T.Q. policy that has been as polarizing as same-sex marriage once was. But for many gay Americans and their allies, the two are of a piece.

“Just knowing that I knew at 12 for sure that I was attracted to men — not a doubt ever even crossed my mind — I’m sure that these kids know their bodies and know in their brains this is who they are,” said Matthew Hansell, one of the plaintiffs in the 2015 marriage case who spoke with The New York Times this week.

“My husband is nodding his head yes,” Mr. Hansell added.

The case, Obergefell v. Hodges, combined several lawsuits filed by gay couples in Michigan, Ohio, Kentucky and Tennessee who either sought a marriage license or recognition of their same-sex union that was legally performed in another state.

Several couples involved in that case said they saw parallels to what transgender youths are facing now with a patchwork of state laws. At least 30 states still have statutes or constitutional amendments banning marriage equality, though they cannot be enforced because of the Supreme Court ruling. Over the last four years, 27 states have enacted partial or total bans on gender-transition treatments for minors.

“It’s shocking to me that the country cares enough to legislate against these kids,” said Sophy Jesty, 53, one of the plaintiffs in the Obergefell case who now lives with her wife, Valeria Tanco, and their two daughters in Charleston, S.C.