It's undeniable. I am a parent. And this is how I know:
While driving to work today, I crossed over a highway bridge. You know the kind, they get you from one motorway to the other one in a relatively organized speedy fashion. In fact, you almost don't even know they're a bridge because they look like a highway ramp. The thing that gives it away is the slightly poopy-stagnant-stale-water smell that permeates the air as you drive along. All of my life.....well, all of my driving life....I've referred to it as 'bridge smell'. I know what it is, and when there are no other people in the car and I haven't tooted, I know exactly what it is. When there are others in the car, it can be fun to blame it on them.
As I said, I was driving to work. Alone. All by myself in the car.
While on this bridge, I smelled bridge smell. However, this time I didn't wrinkle my nose and say under my breath 'blech, bridge smell'. Instead, I experienced the stomach dropping horror that every mother knows when they think; "Oh crap, I hope she hasn't blown that diaper out all the way up her back!" Indeed, I got so far as to think where I could change such a disaster before I realized....I'm alone. Bridge smell, Audrey. Bridge smell.