Vivian Has Trans Identity Restored In Paper Mario: The Thousand-Year Door Remake

Birdo is seen by the island's robot police officer as he/she comes out of a public potty. (The line he delivers as he comes out: "Wow, that was huge. That was like giving birth.")

The officer throws him in jail for using the ladies' room when he's clearly a man. Birdo asks you to go to his/her house and find "evidence that I'm a woman." So you do. This is how it happens. As you walk into Birdo's bedroom, you hear ... a buzzing. The pillow on her bed is vibrating and buzzing. You walk up to it, and Captain Rainbow looks under the pillow to find ... an item that's censored out on the screen. It's covered up with a question mark. "Proof that the owner is a woman," it says, leaving it at that.

So you bring what is in all likelihood Birdo's vibrator back to the police robot, who accepts it, whatever it may be, as prima facie evidence that Birdo is a chick.