IVF alone can’t save us from a looming fertility crisis

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I've just learned that July 11 is World Population Day. There are over 8 billion of us on the planet, and there'll probably be 8.5 billion of us by 2030. We're continually warned about the perils of overpopulation and the impact we humans are having on our planet. So it seems a bit counterintuitive to worry that, actually, we're not reproducing enough.

But plenty of scientists are incredibly worried about just that. Improvements in health care and sanitation are helping us all lead longer lives. But we're not having enough children to support us as we age. Fertility rates are falling in almost every country.

But wait! We have technologies to solve this problem! IVF is helping to bring more children into the world than ever, and it can help compensate for the fertility problems faced by older parents! Unfortunately, things aren't quite so simple. Research suggests that these technologies can only take us so far. If we want to make real progress, we also need to work on gender equality.

Researchers tend to look at fertility in terms of how many children the average woman has in her lifetime. To maintain a stable population, this figure, known as the total fertility rate (TFR), needs to be around 2.1.

But this figure has been falling over the last 50 years. In Europe, for example, women born in 1939 had a TFR of 2.3-but the figure has dropped to 1.7 for women born in 1981 (who are 42 or 43 years old by now). We can summarize [the last 50 years] in three words: declining,' late,' and childlessness,'" Gianpiero Dalla Zuanna, a professor of demography at the University of Padua in Italy, told an audience at the annual meeting of the European Society of Human Reproduction and Embryology earlier this week.

There are a lot of reasons behind this decline. Around one in six people is affected by infertility, and globally, many people aren't having as many children as they would like. On the other hand, more people are choosing to live child-free. Others are delaying starting a family, perhaps because they face soaring living costs and have been unable to afford their own homes. Some hesitate to have children because they are concerned about the future. With the ongoing threat of global wars and climate change, who can blame them?

There are financial as well as social consequences to this fertility crisis. We're already seeing fewer young people supporting a greater number of older ones. And it's not sustainable.

Europe today has 10% of the population, 20% of gross domestic product, and 50% of the welfare expense of the world," Dalla Zuanna said at the meeting. Twenty years from now, there will be 20% fewer people of reproductive age than there are today, he warned.

It's not just Europe that will be affected. The global TFR in 2021 was 2.2-less than half the figure in 1950, when it was 4.8. By one recent estimate, the global fertility rate is declining at a rate of 1.1% per year. Some countries are facing especially steep declines: In 2021, the TFR in South Korea was just 0.8-well below the 2.1 needed to maintain the population. If this decline continues, we can expect the global TFR to hit 1.83 by 2050 and 1.59 by 2100.

So what's the solution? Fertility technologies like IVF and egg freezing have been touted as one potential remedy. More people than ever are using these technologies to conceive. An IVF baby is born somewhere in the world every 35 seconds. And IVF can indeed help us overcome some fertility issues, including those that can arise for people starting a family after the age of 35. IVF is already involved in 5% to 10% of births in high-income countries. IVF has got to be our solution, you would think," said Georgina Chambers, who directs the National Perinatal Epidemiology and Statistics Unit at UNSW Sydney in Australia, in another talk at ESHRE.

Unfortunately, technology is unlikely to solve the fertility crisis anytime soon, as Chambers's own research shows. A handful of studies suggest that the use of assisted reproductive technologies (ART) can only increase the total fertility rate of a country by around 1% to 5%. The US sits at the lower end of this scale-it is estimated that in 2020, the use of ART increased the fertility rate by about 1.3%. In Australia, however, ART boosted the fertility rate by 5%.

Why the difference? It all comes down to accessibility. IVF can be prohibitively expensive in the US-without insurance covering the cost, a single IVF cycle can cost around half a person's annual disposable income. Compare that to Australia, where would-be parents get plenty of government support, and an IVF cycle costs just 6% of the average annual disposable income.

In another study, Chambers and her colleagues have found that ART can help restore fertility to some extent in women who try to have children later in life. It's difficult to be precise here, because it's hard to tell whether some of the births that followed IVF would have happened eventually without the technology.

Either way, IVF and other fertility technologies are not a cure-all. And overselling them as such risks encouraging people to further delay starting a family, says Chambers. There are other ways to address the fertility crisis.

Dalla Zuanna and his colleague Maria Castiglioni believe that countries with low fertility rates, like their home country Italy, need to boost the number of people of reproductive age. The only possibility [of achieving this] in the next 20 years is to increase immigration," Castiglioni told an audience at ESHRE.

Several countries have used pronatalist" policies to encourage people to have children. Some involve financial incentives: Families in Japan are eligible for one-off payments and monthly allowances for each child,as part of a scheme that was recently extended. Australia has implemented a similar baby bonus."

These don't work," Chambers said. They can affect the timing and spacing of births, but they are short-lived. And they are coercive: They negatively affect gender equity and reproductive and sexual rights."

But family-friendly policies can work. In the past, the fall in fertility rates was linked to women's increasing participation in the workforce. That's not the case anymore. Today, higher female employment rates are linked to higher fertility rates, according to Chambers. Fertility rises when women combine work and family life on an equal footing with men," she said at the meeting. Gender equality, along with policies that support access to child care and parental leave, can have a much bigger impact.

These policies won't solve all our problems. But we need to acknowledge that technology alone won't solve the fertility crisis. And if the solution involves improving gender equality, surely that's a win-win.

Now read the rest of The CheckupRead more from MIT Technology Review's archive:

My colleague Antonio Regalado discussed how reproductive technology might affect population decline with Martin Varsavsky, director of the Prelude Fertility network of clinics, in a roundtable on the future of families earlier this year.

There are new fertility technologies on the horizon. I wrote about the race to generate lab-grown sperm and eggs from adult skin cells, for example. Scientists have already created artificial eggs and sperm from mouse cells and used them to create mouse pups. Artificial human sex cells are next.

Advances like these could transform the way we understand parenthood. Some researchers believe we're not far being able to create babies with multiple genetic parents or none at all, as I wrote in a previous edition of The Checkup.

Elizabeth Carr was America's first IVF baby when she was born in 1981. Now she works at a company that offers genetic tests for embryos, enabling parents to choose those with the highest health scores.

Some people are already concerned about maintaining human populations beyond planet Earth. The Dutch entrepreneur Egbert Edelbroek wants to try IVF in space. Humanity needs a backup plan," he told Scott Solomon in October last year. If you want to be a sustainable species, you want to be a multiplanetary species."

We have another roundtable discussion coming up with Antonio later this month. You can join him for a discussion about CRISPR and the future of gene editing. CRISPR Babies: Six years later" takes place on Thursday, July 25, and is a subscriber-only online event. You can register for free.

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