It's a mother thing

It comes with the contract when they place that little bundle in your arms. 

The diaper the little darlin' is wrapped in?

That's not a diaper. It is contract assigning mothers to XX,XXX number of hours of worry.

At first the worries are simple diaper rash. Than it is school not just grades but social adjustment.

Even when said child is a full adult mothers have not fulfilled the worry hours.

Just put that kid on a plane and we can check off a few more hours. A high school friend, a college friend, and my housemate have all expressed concern about their kids when they are in the air.

I've used the phrase that when Llara flies I'm in the cockpit with the pilot. When my housemate's kids fly I let her chaperone the pilot and I work on the copilot making sure they are worthy of shuttling the bundles that are as precious when fully grown as when the stork delivered the to our door.