If you have a pokemon that you can only get once, like hitmonlee/hitmonchan and you want tyrogue, catch a ditto in the altering cave (Note:they will be around level 60)Put your
hitmonlee/hitmonchan in the daycare center found on island 4 wait a while and come back.If the man in front is standing further out he will say your pokemon had an egg.Take it and walk 6,400 steps and it will hatch into a baby level 5 tyrogue

PS tyrogue is a male only species

PSS this will work for many other pokemon.