uhh mostly adventurers don't have the likes and interests needed to build a relationship to lovers, but then again I saw a goblin adventurer hold a grudge with someone so it might be possible just finding the right combination of traits to match up for a lover relationship or that grudges are not tied to marriage and free to be access.
either way I'm doing what I did 5 years ago and trying to get children through the pet system.
that said the only news of that happening is through world gen so chances are your adventurer 'could have adopted.'
Ok...
Go play the latest version of dwarf fortress, then come back to this conversation. How is a strong need to 'make romance', 'socialise' and a 'dream to raise a family' lacking the interests required to build a relationship? Those are all unmodded vanilla adventurer needs (pretty annoying ones too as you can't actually fulfil them as a player!).
I'm not saying that definitely means retired adventurers can now have children, but things have moved on a lot in the past 5 years and it's worth investigating to see how much has changed.
the process of doing this takes a whole lot of waiting either way.
also what I mean 5 years ago is bypassing the marriage mechanic to setting up pet breeding just to prove Adventurers can breed wayback when there was no retired player forts and you had to move on top of an already existing site to play that adventurer, or kill an adventurer to park a companion adventurer there to pull that off.
now most of the stuff you had to do modding or hacking is now in vanilla so I'm back on this experiment to see if it's done with lil to no modding.
that all said there another player testing out the worldgen thing with 20 human adventurers in the adventurer !!science!! thread hoping the best of luck for them.
side stepping this tangent because I think we are on the same idea of testing to see if this works,
I think embarking over bandit camps to score their loot in fort mode after you killed them all in adventure mode is an idea, you could possible move the adventurer who did it to the fort.
your adventurer could avoid getting hammered by becoming a lord or becoming the hammerer.