About three years ago, a New York judge allowed a gay man to adopt the child he was already raising with a female friend. The two friends tried conceiving a child through insemination but were unsuccessful. They remained committed to co-parenting and arranged to adopt a child from Ethiopia. Because they were not married, only one could adopt the child overseas. The woman adopted the child and returned to NY, where the two petitioned to have the man do a second-parent adoption. In that case, the court had to find that the two friends met the definition of "intimate partners" in the statute.
I want to give a shout out to Angela Kupenda, who wrote twenty years ago about the model of two African-American adults adopting a child together in circumstances where each might hesitate to take on parenting alone.
This isn't uniquely a gay rights issue, but being gay means pregnancy will not happen by chance. It will take planning. It calls out for creativity, more creativity than is found in limiting joint parenting to married couples of any gender combination.