New survivors can be acquired through recruitment missions, sometimes appearing through random events whose occurrence can be increased or decreased based on research and policy, and by destroying factions you have the option of recruiting 2 unfortunate survivors.
Some survivors may have a child with them, which works as a disadvantage for the characters who "equip" them. Children act as an item that is not a weapon that reduces all statistics but increases happiness. Children consume half a unit of food every day. Unless the fort's "Children must go to school" policy is in effect, each child must be equipped with a survivor or the game will automatically assign a survivor to equip the child. Each child has an instant hint that shows their age, and 13-year-olds have a chance to "grow up" at 14 and be converted from an item that is not a weapon to a full-fledged survivor who needs housing and can be sent missions.