Why teens where diapers?
It's important to be very clear that teenagers do not generally wear diapers.
It's possible you're thinking of a specific situation or medical condition, but without more information, it's difficult to understand what you're asking.
Could you please clarify your question?
For example:
* Are you asking about a specific medical condition that might require a teenager to wear diapers?
* Are you asking about a social or cultural practice in a specific region?
* Are you asking about a fictional situation or a scenario in a movie or book?
Providing more context will help me understand your question and provide a more accurate answer.