It's fiction, but Marge Piercy's novel Woman on the Edge of Time (1976) is interesting for how she constructs a 'gender-neutral future utopia' very much along the lines of 1960s/70s counterculture ideals.
The novel has an abused Latina woman committed to a psychiatric hospital in 1970s New York discover she can time travel (although it's also possible she hallucinates her trips to the future). To talk only about the gender and sexuality of the 'future' -- she often can't tell whether people are male and female, because it's an outdoor collective agriculture world where everyone is very fit and muscular and as they don't obey 20thc clothing or behavioural norms, she keeps thinking women are men, because their body language is free and self-confident in a way she associates with men.
Men and women fight on the front lines in war. Rape is a crime of the past and there's no more marriage. The norm seems to be polyamorous and bi. But the key thing is that (it's never explained how it's done) women no longer give birth. All babies are born centrally in a sort of birth tank, and have three parents, who can be of either sex, at least two of whom BF (men are given hormone treatments to allow this) with no genetic link to them. Everyone lives in their own small house, and babies and children are looked after centrally until they are adults at about 14/16, and move to their own living quarters.
It's worth a read, even though it's hugely problematic in lots of ways. (There's also a nightmarish future dystopia in the novel where the world is so polluted the rich live on space platforms and harvest organs from the poor, and everyone is owned by companies -- where women are are surgically modified to look like Barbie dolls.)
One of the things that's interesting is that the woman from the 1970s often views the future Utopians as 'childish' because of their lack of the gendered behaviour, self-presentation and ritual she associates with adulthood.