The breeding you describe only happens for Pokemon where the male and female are different species (i.e. different Pokedex numbers).
So this is only the two families you mention. Not Plusle/Minun or anyone else.
- Breeding Nidoran♀ with any compatible Pokemon will yield either Nidoran♀ or Nidoran♂.
- Breeding Nidoran♂ with Ditto will only get you Nidoran♂.
- Breeding Illumise with any compatible Pokemon will yield either Illumise or Volbeat.
- Breeding Volbeat with Ditto will only get you Volbeat.