BabyMage

The story of how you discover your girlfriend wears diapers and what happens after that.

You find yourself in a future where medical science has extended human life far beyond its current limits. As a result, parents often choose to extend their children's childhood and even infancy for hundreds of years. To enable them to take care of these fully-grown children, adults undergo treatment to make themselves four times larger.

You are Michael, a man who, just days away from his 21st birthday, still lives with his parents and his 19 year-old sister, Jane. You wake up one morning wearing a diaper and find that your room has become a nursery. It becomes clear that, even though you clearly still have your 20-year-old body and need a giant cot and adult-sized diapers, something is warping everyone else's minds so that they treat you like an 11-month-old.

When unemployment forces you to move in to your mother-in-law's house she has total power over you. She uses it to make you live as her baby girl.