Recapitulation theory ("ontogeny recapitulates phylogeny") puts forth that incubating humans act out evolution as they grow from zygote to baby. This was a popular idea a century ago, but it's turned out the science isn't that simple. Yet the principle holds that the dividing fetal cells are engaged in a kind of performance of all of evolution—from simple to complex, from general form to specific form. The developing human loses its tail early, gains a cerebrum later.
Thus newborns are time boiled down, and every ounce gained is another 20 or 30 million years of life; they compress the three billion years since abiogenesis into a nine- or ten-month performance that runs from conception to birth. By the time they arrive they have gone for rides on comets, teased dinosaurs with sticks, come down from the trees, and run across the savannah.
The day before we were scheduled for our Caesarean I told the Internet that I was packing for a very long trip and wasn't sure what to bring. People—friends and strangers—wrote with suggestions: Spare pants. A suitcase filled with books. Your wife. Extra underwear and camping detergent; a hoodie and a flask. The head and <3. Can organic mixed nuts, first aid kit, cash hidden in wallet belt, an extra pair ultra comfortable shoes. Carseats. Toothbrush. Multiple chargers. Take less. Pillows and a blanket for you, easy snacks, every kind of memory-recording device. Bring a sandwich. Music. And patience. Half the clothes and twice the money, and lots and lots of gin.
So a few days ago we packed everything and went to the hospital. And a few hours after we arrived the clock—our clock—reset from 3.5 billion to zero.
Hello little girl. And two minutes later: Hello little boy.