tjameswhite.com

… apparently it’s ok. At least according to the book I’m reading:

In 1999, English housewife Jill Fulough got a fright late one night when she saw green sparks shooting out of her sleeping baby’s disposable diaper. She called the diaper manufacturers, who assured her that the sparks were the result of triboluminescence, an extremely rare — and perfectly harmless — buildup of energy probably caused by the friction of the baby’s bottom rubbing against the inside of the diaper. (It’s actually exactly the same chemical reaction that produces the sparks you see when you bite down on a Wintergreen LifeSaver in a dark room. Unlike static electricity, it doesn’t generate any heat.) The boy apparently slept through the entire episode, and there’s no record of any injury to anyone.

The New Father

So, there you have it.