The game engine periodically takes a census to determine the current population of the village. All villagers within the horizontal boundary of the village and within 5 vertical blocks of the center will be counted as part of the population to determine if continued villager mating is allowed. However, any villager within the horizontal boundary of the village and within a vertical distance of 32 blocks downwards of the center of the village will attempt to enter mating mode as long as there is at least one villager within the boundary. If two villagers simultaneously enter mating mode while they are close to one another, they will mate with each other and produce a child.