GameGear is based on the Master System hardware and got more colors, sound channels, and a smaller resolution. Because of these extra functions, GameGear games cant be played natively on a Master System or a Genesis. You can find patches online that converts GameGear roms into Master System compatible software, but then you need a flashcard to play them. Your other option is to get a GameGear and mod it with one of many TV Out options that you can find with Google. I think some GameGear games are sold as VC titles on Wii U. The last option is... using an emulator. On PC or on a modded console, like the Wii or original Xbox.
have you ever tried to mod a gamegear so you can play it on tv?