Here are random children tips:

Children can provide food by foraging mushrooms, just put a child on a mushroom when one appears. Adults can't forage mushrooms.
Children won't work until they are 14
When putting a child on another, they will automatically play with each other
Children can heal a sick villager. This will improve their healing skill.
(in previous games children could gain Farming Skill by picking up mushrooms, but I haven't noticed this in this version of the game yet)
Children will have their adult's voice at the age of 11
Adults cannot have babies before they are 18
Nursing mother will stop working until the baby is 2 years old
Upgrading Medicine will increase fertility rate and chances to have twins or triplets
Twins and triplets will be identical in appearance and skills and will share the same likes/dislikes but won't have the same name.
Twins and triplets will always be all boys or all girls. You cannot have fake twins.
Children can inherit skills from their parents
The game doesn't take into account families ties, so your villager can have babies with his parents, siblings, or his own children if they are 18(it's weird, but hey, that's how the game works, I'm not responsible).
If you activate "auto-breeding' option from the skill menu, the villager will constantly try to have babies with all the adults available (including his own family) if it's a woman, she will have babies with all the adult males of the village. If it's a man, he will constantly try to have babies with all the women who don't already have babies.
If your villagers have difficulties having babies, try to upgrade the medical tech, or try a different couple of villagers.
Your village as a limited population number, which can be increased by crafting more huts. The maximum population number is 100
Fertility decrease with age. An 18 years old villager have more chances to procreate than a 50 years old villager. After 40 years old having babies is really hard, but possible if you insist a lot.
Children can die just as adults, so pay attention to their health.
If a nursing mother dies, the child won't die and automatically age to 2 years old.