How to change rival's gender

[Epicjon]

I'm hacking pokemon firered, but I'd like to make the gender of the rival the opposite of the player like in emerald, can I do that?

[haven1433]

Rival gender isn't a feature in FireRed.

With a few exceptions, HMA is about showing you the data in the game and getting you edit it, but it doesn't try to add new customizations like this.