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.
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