Think of the things that could have happened, any one of which would have terminated our germ line and nullified our existence.

We think of our present, an individual thing,
But us to the world, family history did bring,
And that, dear friend, is quite simply, chance,
From hormone’s whim, and the mating dance.

We wonder that we live and draw breath,
Given that our ancestors often faced death
Before finding a suitor with which to be,
And grow more branches on our family tree.

So whatever the circumstance or social event,
We’re glad that together our ancestors went,
And across the generations of joy and pain
Made possible our node on life’s linked chain.

But if a precursor’s eye hadn’t had its gleam,
Or another lost through damp of a dream,
Or a single progenitor just not in the mood,
Germ line thus severed — My my, how rude!

Then our place’d be held by a different soul,
And we’d be in life’s fabric an invisible hole.
So backtrack your life-thread however far,
But for ancestral coupling thank a lucky star!