Pokemon bears the egg while trainin. Pokemons are being trained at NPC Kate that is located in Fuchsia. It works like that, when we give same pokemons of the opposite sex to the training. They will feel special bond while training and when this bond gets to the 100%, these pokemons keeps training together and they are trying to get child. When the correct time happens female lay egg. We can make egg of the pokemons listed below. First step, that deducts pokemons their intimacy (From 0 to 100%) continues for 2 weeks. Then we wait again 2 weeks for egg. Later without taking out pokemons, they can become parents again. As the first stage they have behind, this time of realization is shorter - we wait 3 weeks.
In order to hatch egg we have to keep them in our bag and carry it everywhere with ourselfs.