While Pokemon Sword and Pokemon Shield may be the current focus of the Pokemon community, there's been a surprising leak from a previous generation. The leak claims to show an interesting angle that the Pokemon franchise could have gone in, but ultimately didn't, featuring supposed Pokemon sprites from Pokemon Diamond and Pokemon Pearl. These sprites show that Game Freak, at some point, considered making unique visuals for each Pokemon's gender.
The leak reportedly comes from a beta version of Pokemon Diamond and Pearl, leaked to the community just this past week. The leak includes hundreds of sprites taken from Gen 4 of Pokemon and was originally posted to 4chan. As can probably be assumed, 4chan leaks are typically highly unreliable. Those within the Pokemon community seem to believe it's accurate, however, based upon comparisons to pre-launch marketing for Pokemon Diamond and Pearl. It would be an impressive fake, given the detail of the sprites and their accuracy.
Hundreds of sprites released, many of which were identical to their official counterparts in Pokemon Diamond and Pearl. But among those sprites were entirely new ones intended to be used as gendered sprites. For example, the male and female Pikachu have different ears and tails, while the male and female Bulbasaur have different spots. It's possible that Game Freak was seriously considering creating unique gendered sprites for all Pokemon in Pokemon Diamond and Pearl, but that the plans were ultimately scrapped for one reason or another.
Why they were scrapped remains a complete mystery, but Pokemon fans can probably guess given the recent controversies surrounding Pokemon Sword and Shield. Game Freak started animating sprites in Pokemon Diamond and Pearl, and having to animate twice as many sprites would be quite a bit of work. Now imagine having to animate twice the number of models in every generation after that - Pokemon Sword and Shield's PokeDex might have had to be cut in half from where it is. As interesting as the feature might be, it was not a workable feature looking toward the future.
While the legitimacy of the leaks is still questionable due to its source, there is some evidence it's true. For example, there's a gendered sprite for Mudkip actually in Pokemon Sword and Shield's official files, and it's the same sprite as shown in the beta leak. There's also an old 2006 Corocoro article that states male and female Pokemon will be "visibly distinguishable in most, if not all, cases." It seems unique Pokemon sprites for different genders were once Game Freak's official plan.
Pokemon Diamond and Pokemon Pearl are available for the Nintendo DS.
Source: Lava Cut Content