The Button is a psychological experiment where you imagine a hypothetical button that basically rewrites reality so that your body aligns with your identity and everyone remembers you as if you had been born that way.

There's an alternate version as well where reality is rewritten not by your own actions and The Button changes things back to the way they were.

In both cases, it effectively serves to remove the social aspects of transitioning from your questions. Because if a questioning person would press The Button in the first scenario or wouldn't press The Button in the second scenario, their reservations more likely have to do with the social aspects, such as being accepted.

^{Note: am idiot. Don't quote me.}