I think i can confirm that physical isolation is a good contraceptive - for dwarfs. Definitely not for animals, but for dwarfs it really does reduce or prevent pregnancies. Rith has been isolated from her husband for just under thirteen years now and hasn't had another child. Her three children have all grown up now and i've reduced most activities to ordinary maintenance.
For some reason, trees have largely stopped re-growing, so doing anything ressource-consuming turns into massive travels all over the surface, not to mention depletion of what little wood remains. I suspect "tree space" is getting hogged by cavern trees, preventing others from growing up.
Rith has become even more legendary at clothesmaking, is a legendary farmer and high-level thresher, woodcutter and carpenter, as well as a decent cook and brewer.
Mebzuth, the eldest daughter, is 18 now, a talented woodcrafter, proficient ambusher (price catch was an elephant) and all-around handydwarf; she's picked up all the odd jobs like beekeeping, animal training, soapmaking and has become adequate in most of them (including waxcrafting). She's also the main hauler.
Tholtig, the son, is thirteen going on fourteen and has done nothing but smoothing the exposed rock faces. He's become an accomplished engraver in well over 1 1/2 years, due to his completely awful speed attributes: he was very clumsy, with poor kinesthetic sense and atrocious spatial senses when coming of age, he's one indicator less clumsy and spatially unaware due to eighteen months of non-stop engraving.
Solon, the youngest daughter, was born after Rith was isolated and was one of the last dwarfs to mood on the site before i disabled artefacts. She's a legendary bonecarver, but for now i've put her on fishing duty, to have another source of food and another crafting material.
The two other children who were thrown out of the underground compound, Led (boy= and Mebzuth (girl) are just over two and just under three years away from growing up. I'm not too sure of what i'm going to do with them apart from marry them off as soon as possible.
A single cage trap (we had four stones, three of which were converted to mechanisms, and two of those were needed for the screw press) captured two chinchillas and three wolves. The wolves were of different genders, so a small wolf farm has sprung up. Perhaps i should mod them to be trainable, this could eventually allow turning invaders on...