The Fall changed the world...
Young females are separated from males during the last years in the creche. Instead of leaving the creche for an apprenticeship, they enter the Hare-em. A protected sanctuary where they keep training until such a time that they choose a mate for coupling.
The old tradition of marrying daughters off for influence and wealth lives on, although slightly changed it is known as coupling. The value of such couplings have given rise to a new profession known as genomancer and the trade of fertile daughters between cities is a key to continued survival of the Fortress Cities.