keep breeding them til you see her with a baby in her arms - once you see the baby being held in their arms - when you go to the details screen it will show you how long you have til the baby will be weaned - if your villagers are not having thier baby rt away - just be persistent - it can be trying to get that first child, just keep dropping them on top of each other til you see a baby - you dont have to let them go to the "Love shack"