You find a strange item. It looks like a keychain-sized flashlight, but the bulb on the end is blue.
The instruction booklet taped to it explains how to use it. You can switch it to give off blue or pink light. The flashlight changes people's sex. Blue, of course, makes someone male and pink makes them female. Brighter light makes someone more feminine or more masculine than dim light.
But the most astonishing thing you read is that whatever changes you make, anyone except the user will think they're perfectly normal.
You think the idea is ridiculous, but you try it on yourself. You switch the flashlight to pink and shine pink light on your chest. Immediately, your breasts grow, and your undershirt transforms--it feels different, it must be a bra now. The light just has to be magic. Then you notice a knob on the flashlight. You turn the knob and the light gets brighter--and the light on your chest now gives you bigger breasts.
You switch the light to blue and shine it on your chest--soon everything is back to normal.
Paying for the flashlight, you leave the store for the mall. You spot a guy from your dorm and as an experiment you shine some pink light on his left hand. Then you say "Hi, Gene".
"Oh, hi," he replies.
"Your hand," you say.
He lifts up his hand. It's now a thin woman's hand, complete with nail polish. He looks it over and says "What?"
"Oh," you say. "I thought you broke a nail."
"Must have been your imagination," says Gene. He didn't even realize he wasn't supposed to have a woman's hand. You turn the flashlight to blue and shine it at his hand for just a second. It's back to normal, and he still doesn't notice.
So you have a magic sex-changing flashlight, for real. You decide to....