I have no idea how scientists even got the idea to TRY this.  At least one of them MUST be some kind of deviant

A team of scientists at the Guangzhou Institutes of Biomedicine and Health in China has figured out how to grow real human teeth...out of HUMAN PEE.

They found that they could use the urine as a source of stem cells.  And when they harvested them properly and implanted them in lab mice, they were able to grow the beginnings of real teeth.

This is still a LONG way off from being a possibility for people who need teeth...you're not going to be using a pee mouthwash to grow yourself a sturdy set of new chompers anytime soon.

But the researchers say it's the first step in figuring out how to actually regenerate human teeth.

(BBC)