Crappy oekaki stuff.
READ THE STORY
After Cynthia beat the champion, she in great glee, decided to throw a private party with her pokemon. Unfortunately every single one of her pokemon had fainted, with Lucario being the sole survivor. So there they were, all alone in Cynthia's room, breaking into professeur Oak's secret stash of rum.
Soon Lucario, after getting severly drunk, got the amazingly bright idea to offer himself to the first person he sees. Which of course, with only one other soul in the room, is Cynthia.
And Cynthia who wits are equally addled takes up on his offer.
Due to say, that morning Cynthia and Lucario agreed to never mention what had happened that fateful night.
And Cynthia didn't get pregnant.
Disclaimer: I do not support or condemn pokemon/human pairings. Unless it amuses me.