Making villagers breed in Minecraft is a little more complicated than the breeding of any other living creatures in the game. However, it is quite easy to make villagers have babies and the process of doing so will typically result in the construction of a good village.
There are 2 factors that come in to play when it comes to villager breeding.
- Space - There needs to be enough room for more people. This is determined by the number of doors. The more doors, the bigger the game thinks the village is. It is of course very easy to cheat this by just building a load of doors and not actually having to attach them to a house of any kind.
- Willingness - Yes, the villagers need to actually want to reproduce, they won't just do it because the conditions are right.