The adoption proved a shrewd decision. Naegle, as next of kin, had visiting privileges when Rustin was hospitalized for a perforated appendix and peritonitis and was eventually executor of the will. Despite the oddness of the arrangement, it was, all things considered, legally seamless.

Now that marriage equality is an American right, partner adoptions are hard to fathom, an artifact of an earlier societal paradigm that, in a remarkably short period of time, has come to seem inconceivable. “People today really have a hard time remembering, let alone feeling, what it was like to be an outlaw — to be truly strangers to the law — shoved out of every legal system, and then persecuted,” said Evan Wolfson, founder of Freedom to Marry, an organization that, for more than a decade, has played a large role in the passage of same-sex marriage legislation. It is easy to forget that an American state would not decriminalize sodomy until 1961; that as late as 1966, gays and lesbians could not legally buy a drink in a New York City bar; that even after the Stonewall riots, in 1969, the American Psychiatric Association considered homosexuality a mental illness. As recently as 2000, civil unions were still not widely available and domestic partnerships didn’t offer federal protections.

Adult adoption by gays and lesbians has only been quietly discussed, both in or outside the gay community, for fairly obvious reasons; there isn’t an easy way to tell your friends and family that the man or woman with whom you share a bed is, legally, your son or father, or your daughter or mother. Consequently, there are no reliable data — or even flimsy data — as to the number of such adoptions, and experts in the field are unwilling to hazard a guess. The practice seems to have taken hold amid the tumult of the 1970s and 1980s, during rampant discrimination and the onset of the AIDS crisis.

For those couples who adopted in past decades, the years of piecemeal state-by-state legalization, and the Supreme Court’s 5-4 ruling in Obergefell v. Hodges, which legalized same-sex marriage nationwide, ended a long period during which men and women, in exchange for medical, financial and legal benefits, pretended to be something they emphatically were not. But until such couples, most of whom are now elderly, unwind their adoptions, their relationships are either stranded in a kind of limbo or something worse: Courtney Joslin, a professor of law at University of California, Davis, said that couples who marry without voiding the adoption may in some states be subject to “a criminal incest statute.” (As of 2012, 25 states and territories considered relationships between adoptive parents and their adult children within the definition of incest.)

For the time being, a lot rests in the hands of the judges, who have the power to vacate adoptions. Elizabeth Schwartz, who practices L.G.B.T. family law in Miami, hopes they will “embrace the opportunity to bring justice. That’s their job, to do the right thing and to use their equitable powers to right past wrongs.”