I'm trying to breed a Riolu with a Ditto but i'm not getting any eggs. Can someone tell me my problem? Do I have to evole Riolu into a Lucario in order to breed a Riolu or do I breed a female Lucario with another Pokemon? .
Baby Pokémon like Riolu cannot breed with anything, even if it's the same species and opposite gender. To breed a Riolu, you have to evolve one or get a Lucario, then you can use the Ditto.