Many fine entries in hand; keep them coming.  One line of reasoning predominates, well illustrated by this submission:

"Birth consistently leads to death.  There are often events of interest to someone between the two.  Aside from fairy tales, I know of no more reliably consistent slippery slope.

"More pop into my head, but following on their heels are exceptions.

"Here is a chain of events for you:

"Birth leads to toilet training.  Toilet Training leads to puberty. Puberty leads to adulthood.  Adulthood leads to death.  Of course, it isn't entirely consistent given that some do not achieve all steps."

More later.