Egg Group/Breeding chains

Many Pokémon are included in two different Egg Groups and can form what are known as breeding chains. These link many unrelated Pokémon together, allowing moves that would not normally be accessible to certain Pokémon to be legal, like on.

TMs are also passed down through breeding from the father. Any move in the father's current moveset that can be learned via TM, Egg Move, or Move Tutor (in Crystal) will be passed down to the Pokémon hatching from the Egg.