This seems like one of those technologies that's TOTALLY UNNECESSARY, but would actually be pretty convenient if it went mainstream and was affordable. Scientists from Penn State University have created a "smart diaper" with a built-in sensor that's able to send parents a push notification on their phone when their child's diaper needs to be changed, according to the NY Post.
Not only that, but it can provide LEVELS OF DIRTINESS maybe like, "There's a little tinkle" to "Holy hell you're gonna need gloves for this one!" The smart diapers are made of paper, and include sodium chloride, graphite, a circuit board, and a tiny lithium battery.
Once it gets wet, the graphite reacts with the liquid and sodium chloride and as it's absorbed by the paper, electrons will set off a sensor. The diapers are still in the development stage so it's unclear when they'd be available and, more importantly, how much they'd cost. So for now, you'll have to stick to checking the diaper yourself like usual.