Playing Game Gear games on a Gameboy?

I don't remember where I read this, but I believe I read somewhere that somehow it's possible to take a ROM and put it on a blank Gameboy cartridge. What kind of Gameboy, I don't know, and that's part of what I was wondering.

So, if this were possible, would I just get a blank GB cart and put the ROM on there? How would I even do that?

Just sorta a random thing I was thinking about while playing Sonic Chaos earlier.

You can play Game Gear roms in GBA with a flashcard.

Ah, interesting. Now, where would I get a GBA flashcard, and how would I put the ROM on it?

Why do that when you could just play them on a laptop or computer with an emulator? Better graphics too probably when playing on a computer.

Yeah really.

Ditto. Playing them on PC is better.