Mine

there is no information on Professor Oak's parents or children. His grandson, Gary Oak, is a wandering Pokémon trainer turned researcher and former rival of Ash Ketchum, the protagonist of the Pokémon television series. Gary's rivalry with Ash ends when he becomes a researcher, paralleling Oak's old rivalry with Agatha (though, that old rivalry is game-canon, while as Gary becoming a researcher is anime-canon; Gary remains a trainer in the games).