Month: March 2018

Demography of IVF and World Population

Predicting the future is fickle, as Stephen Hawking once observed: “it exists only as a spectrum of possibilities.” And, yet, divining the future is irresistible and physicists strive to forecast the future of stars, black holes and climate. Biologists are more chary, although even they venture to predict extinctions. I recently indulged my curiosity, not by straining at tea-leaves or astrological charts but using math with the help of my son and a statistically-sophisticated friend. We are interested in an aspect of world population that hasn’t stirred much attention. Yet.

The United Nations projects world population growth to the year 2100, but no one has previously estimated the contribution of infertile people. “Eh?” I hear you say. That sounds absurd.

Infertility is an original scourge. Didn’t Jacob’s wife cry, “Give me children or I die!” It was always a private grief with few options, and even fewer effective remedies. I remember a generation or two ago hearing whispers, like, “Why didn’t Uncle Joe and Auntie Jane have children?” No one dared ask them. It was less embarrassing to ask some poor soul if they had cancer. Thankfully, infertility has ‘come out,’ mainly due to attention on revolutionary in vitro fertilization or IVF.  The revolution started a few minutes to midnight on July 25, 1978, when Louise Brown was born as the world’s first test-tube baby.

Male infertility, premature menopause and some other relatively common problems were resistant to standard treatment with pills and surgery, but starting with the hub of basic IVF for bypassing blocked Fallopian tubes, a bevy of new technologies has sprouted. Almost no one is now denied a chance to become a parent if they want, provided they can afford to pay in countries where no subsidy is offered. There is now egg, sperm and embryo donation with freezing for longer-term preservation, sperm microinjection, IVF surrogacy for women without wombs, and genetic testing to avoid a blighted conception (PGD).

Since Louise Brown, about seven million babies have been conceived who would not otherwise exist. The children grow up to be as healthy as the rest of the population, and they become fertile adults. The first ones are now having babies of their own.

How will this industry making babies grow in future? We wanted to know how many will be added by technology to the world in decades to come up to 2100. We were even more interested in the broader question of how many people will owe their existence to IVF either directly as test-tube babies OR as their children and grandchildren as IVF services rapidly expand across the globe. We chose conservative data for our calculations, and expect our predictions will underestimate growth, unless there is a global catastrophe. But our estimates still surprised us.

The paper came out today. It is short, readable and currently offered free until May 15 by the publishers. Click Science Direct. I will send a pdf if you have problems connecting.

Next Post: Calamity in cryopreservation labs

Pug Marks in the Snow and Mind

Winter still grips the Allegheny Mountains. Rain alternates with snow as the days creep toward the official opening of spring. Snowshoe Mountain has accumulated 159” of snow this winter, which is far below the record although we are not yet finished with winter.

Cabin fever feels most febrile when clouds hang low with drizzle, and I wait for bright sunny days with fresh snow to go outside and strap on snowshoes for a hike in the forest and open spaces called ‘balds.’ I spend a couple of happy hours looking at fresh tracks that tell stories about the night-life I rarely see.

There are no tracks of red, gray or fox squirrels because the animals are asleep in leafy dens. Chipmunks are curled up in hollow logs and flying squirrels are nested in my bird boxes. Mother bears stay in their dens for suckling tiny cubs that only weighed a pound at birth, although a juvenile will occasionally wander out to stretch and look for a snack. The day I wrote this log in my nature journal there were no bear tracks.

But there were tiny prints from mice scampering over the snow for a few feet before they dove under. Of all the animals here, I would expect the smallest to hibernate or go into that borderline state of torpor; they must keep their metabolic fires burning to avoid hypothermia. Foxes and bobcats are grateful the rodents are awake, and a hole dug through the snow down to the grass was probably where one pounced on an unseen victim after hearing a murine ultrasonic courtship call. Sex behaviour is often unsafe.

I haven’t seen opossums or rabbits in daylight for months, but their tracks show they were abroad last night. The distance between prints shows they were sauntering across open spaces with a confidence they lack in daytime when they hurry on their way and are ready to dash for cover. One set of rabbit tracks led across an old field where they suddenly vanished, as if the animal had been snatched into the air, but there were no signs of a predator or an Olympic jump. The mystery still dangles.

Our resident striped skunk wasn’t out last night, nor was the coyote pack that patrols the area. As I walked round in a great circle I came upon prints two feet long made by a lumbering biped. Yikes, Bigfoot is here! If only I had brought children along to kid them about the imprint of snowshoes.

The footprints I dream of finding (maybe die to find) look like those of a coyote with four toe pads, but larger and wider and without protruding claws. A panther.

Many local people believe a few still hold out in Appalachia more than a century after they were officially declared extinct. But what is extinction? Is it a complete absence of a species, or the absence of a sustainable breeding population? There have been rare sightings over the years, and a few are hard to deny.

A friend in the DNR was called out one night to a report of a panther feeding on a sheep kill, and he captured it after anaesthetizing the beast with a dart gun. Isolated cases probably escaped from captivity or were deliberately released when they grew too large and wild to be managed. So, it is true that panthers haunt our forests, but mostly stalk our minds. People who live in and around these forests are reluctant to surrender that ultimate symbol of nature’s wildness, and I admit that even the slimmest chance of stumbling on pug marks in the snow brings spice to a walk in the woods.

Next Post: A Costly Thaw

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