Do you believe that certain species of Pokemon in the distant past may have given Live birth and simply evolved to be oviparous?

Actually, current fossil evidence suggests that pokémon had always been oviparous. Even mammalian ones seemed to have evolved from monotreme-like pokémon, rather than from ones that gave live birth.

Of course, this also begs the questions of how Mew gives birth and whether or not Mew is indeed the ancestor of all modern pokémon as is thought by some questionably scientific circles. Personally, I believe that if and only if the story concerning Mew is true, then it’s entirely possible that there was at least one pokémon that gave live birth, but by and large, all pokémon we know about, past and present, laid eggs.