Use the following trick to easily reproduce rare pokemon such as: Charizard, Lapras, etc. Capture a Ditto(this can be found at the cave at cerulean)take it to the daycare couple at island 4 and leave it there, put the pokemon you want to duplicate with the Ditto then get out and travel a little( this is the best way to get an egg easier) then come back until the old man comes uot of the gate and he will give you an egg, the pokemon that will hatch from the egg is the duplicate of the pokemon that you putted together with Ditto. Some Pokemon will not breed in this way(legendary pokemon).