When Louise Brown was born in Manchester in July 1978, her parents' neighbors were shocked to find that the world's first test-tube baby was "normal": two eyes, ten fingers and ten toes. In the 45 years since then, IVF has become the world's leading infertility treatment. At least 12 million people have been conceived between test tubes.
Every 45 seconds or so, an IVF baby is born, taking its first breath of air. IVF babies are just as healthy and ordinary as anyone else, yet to their parents, most of whom struggle for months or years with infertility, they are nothing short of a miracle.
In a world where one in six people suffer from infertility, those successes are rightly celebrated. What is less debated are the problems of in vitro fertilization. Most treatments fail. This subjects women and couples to cycles of hope and discouragement, and gives the assisted reproductive industry an incentive to sell false hope. The obstacle is the lack of progress in understanding the basic mechanisms that determine fertility. Now, at last, science is making headway, offering more promise and less suffering to coming generations of parents.
Over the years, IVF has made its techniques better and safer for women, who bear the brunt of the treatment. The birth rate of twins and triplets has plummeted, reducing the number of risky pregnancies. Hormone treatments are safer. Combined with egg and sperm freezing, donation, and surrogacy, IVF has given many people (including same-sex couples and singles) a chance to be parents they didn't have before.
However, the process is still tiring and expensive. It is physically painful for women and emotionally draining for both sexes. For many, fertility treatment is an unaffordable luxury; in the United States, for example, a cycle can cost 20,000 dollars. Some countries restrict processing in accordance with a conservative moral code. Until 2021, French law only allowed IVF to married heterosexual couples. Many countries, including China, ban egg freezing, which helps extend reproductive years.
Too often, the pain and cost end up being wasted. The 770,000 babies born by IVF in 2018 required about 3 million cycles. Many women undergo round after round of hormonal injections, sometimes going from clinic to clinic. In the United States and Great Britain, about half return home with a baby in their arms, sometimes after several years of trying and up to eight cycles of treatment.
All this has fostered a sector of assisted reproduction that sells to customers who have become regulars and desperate to conceive. When a cycle fails, many clinics offer poorly regulated menus of "add-ins" that do not demonstrably increase the chances of success, or may even reduce them. They charge hundreds to thousands of dollars for a treatment.
All these problems share a root cause. Although reproduction is one of the most basic aspects of human biology, scientists have surprisingly limited knowledge of how new life arises. The essential is obvious: a sperm and an egg must meet. However, many of the cellular, molecular, and genetic underpinnings of conceiving a baby remain a mystery.
Little is known about how a woman's ovarian reserve is set before even birth; or why the ovules decrease in number and quality until menopause, which among mammals is only known in humans and in five species of whales. Also mysterious are the intricacies of how an embryo enters the uterus and connects to the blood supply. Infertility is often categorized under “female health” issues, but male factors play at least some role in about half of infertile heterosexual couples, even if that role is often unclear.
Against all this, IVF is woefully inadequate. It arose as a solution to the obstruction of the fallopian tubes that prevented the mother of Lucie Brown from conceiving. Today, with more couples trying to have children at later ages, it is increasingly likely that the problem is the woman's declining number of eggs. There, in vitro fertilization works by offering more opportunities, collecting more eggs and maximizing the chances that they will be fertilized. The procedure works for the lucky few, but without an entirely new approach and treatments, many would-be parents will suffer one disappointment after another.
Some recent scientific work offers some hope. In Japan and the United States, researchers are harnessing stem cells—which have the ability to develop into any of the body's many specialized tissues—to make eggs from skin and blood cells, a process called in vitro gametogenesis. In Japan, healthy mouse pups have been created from cells originating from the tip of their mothers' tails. Earlier this year, researchers announced that they had successfully produced mouse pups that shared two genetic parents. One had contributed sperm and the other skin, which first became stem cells and then eggs.
There are teams working to apply these techniques to humans. Much remains to be seen as to whether cells safe enough to conceive healthy babies will ever be available. However, research is providing new insights into how sperm and eggs are produced. In vitro gametogenesis means that researchers will no longer have to rely on donated eggs, sperm and embryos for their studies; often generously provided by IVF patients. Other teams use stem cells to build models of embryos (called "embryoids"). Those embryoids will never see inside a womb, but they can help show what happens to real embryos that do.
Over time, new treatments may appear. Homosexual couples could have children as genetically related to them as heterosexual couples. Transsexuals undergoing a sex change could do so without sacrificing their fertility.
All this will take time; that is why in vitro fertilization will continue to be important and that is why it needs investment and regulation. A better understanding of fertility should help increase the success rate of IVF, and reduce its emotional and financial costs. The new treatments could herald the biggest transformation in assisted reproductive technology since the birth of Lucie Brown. Surveys show that many countries have fewer children than desired, partly because motherhood is postponed. If the sexual revolution of the 1960s and 1970s gave women the option of not having children if they didn't want to, nascent technology could usher in a new revolution that will allow women (and men) to have the children they want, when they want.
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Translation: Juan Gabriel López Guix
