What is is pikachu a boy or a girl?

In the Pokémon franchise, Pikachu does not have a set gender. Instead, Pikachu has a 50/50 chance of being male or female, determined randomly when they are caught or hatched from an egg. In the anime and other media, Pikachu is often referred to as male, but this is more of a generalization and not indicative of a specific gender.