I’d hazard to guess that there are also important crossovers with multiple schools of feminism here as well. Not always in easy, uncomplicated ways — but when there are no kids many of the roles traditionally associated with women’s work are either rendered obsolete, invisible, unimportant, or just non-existent. And one of the places where many women in pre-industrial society got their center and power is just vanished.

It also skews all the “world building” in a setting. With no kids society doesn’t look anything like real societies, and that’s going to trickle down into making a weird Disneyland world instead of a real world in just about every facet of the setting.

So a couple of additional random points:

* Many societies base some part of their cultural networking on age-bands. This can be tribal initiation groups or highschool graduates all wearing their class ring to identify with each other. But in any case, having multiple age bands — including seniors and children — is required to make this work.

* For a lot of cultures fosterage and/or hostages (which often come to more or less the same thing, depending on how nasty your culture is) is a critical point of exchange. Raising kids of other kin groups in your own was, once upon a time and across large parts of the world, totally normal and — in fact — required to make society work.

* Speaking of which — putting kids into a setting makes you look at how people raise kids. This can be both cool historically (how did folks actually organize child care? — hint, it wasn’t always “woman stays at home and takes care of the kids born from her own body”) and imaginatively (in a world where women have most of the magic, and are always out changing the world, who takes care of kids? and how? and what does that do to social networks? — let’s imagine other ways society could be other than just the 1950’s nuclear family bullshit).

* Think about what kids mean in your society — like, what is a child and what does childhood mean? At what age do kids get named? At what age do they get their own choices? When do they start work in the house? Outside the house? When do they get married? Are there stages to becoming an adult? All of these things have a lot of nuance and difference across historical (and modern) human cultures — put some thought or research or imagination in here!

* In many cultures age and gender interact in weird ways. “Women and children” for an weird 50’s Euro-American example. Or, did you know, in many parts of Europe through the early 1800s boy children and girl children were all dressed the same? They didn’t get differentiated by clothing as “boys” and “girls” until they were 5 to 9. And then girls kept being dressed the same, and boys wore new clothes and had to prove their “boyness.” Which… man. Right? So what is the interaction in your world?

* Most folks know this, but might not think of it, but kids actually do effect the lives of adults who don’t have kids of their own. The kids of other family members are mentees, need to be sometimes cared for, may be named after you or give you religious obligations. The kids of friends and other social group members may change the ways you’re able to interact, and the types of things you do together. (“Sorry Thrag the Destroyer, can’t go adventuring this week, gotta pick up Matilda from Wizard School….”)

(I’d also go into kids and “acceptable losses” and how I actually disagree there, just based on actual historical accounts of many pre-modern societies, especially the psychotic warrior cultures of northern europe, but I think your point is — in general — valid and don’t want to give the edgelords more fuel. I will say though, it changes your opinion about some “great historical men” when you find out they let their own kids be butchered in order to start a war so they could murder other people and take their stuff.)