One procedure has enabled the births of more than 10 million babies around the world, and nearly 3 percent of United States births per year—and it only became available relatively recently.
People have had children via in vitro fertilization, or IVF, since 1978, though it took around a decade for the technique to become more widely accessible. In the U.S., the use of IVF and the broader umbrella of assisted reproductive technologies climbed steadily between the late 1990s and the early aughts before flattening out for a few years. Then, over the past decade, the number of IVF treatment cycles in the U.S. increased by more than 200 percent.
IVF involves the collection of mature eggs from the ovaries, which are then fertilized by sperm in a lab. These fertilized eggs, known as embryos, are placed in the uterus.
Work toward modern IVF procedures began as early as the 19th century. At the time, wealthy families sought out fertility treatments to ensure their wealth could be passed down, prompting scientists to develop surgical procedures to do so.
Some teams took a different route, making the earliest strides in IVF research. In 1878, Viennese embryologist Samuel Leopold Schenk added sperm to rabbit and guinea pig eggs and observed that it prompted cell division. Then, more than five decades later, Harvard University biologists Gregory Pincus and Ernst Enzmann tried IVF with rabbits. Their paper reported this work as a success, but evidence later revealed that the fertilization had actually occurred within the rabbit’s body.
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Still, this work inspired the Boston-based physician John Rock to test the technique with human eggs. Lab technician Miriam Menkin assisted him by extracting eggs from ovaries removed by Rock from hysterectomy patients. She put these eggs in solution, cultured them, and added sperm in a petri dish. Over nearly six years, she attempted to fertilize more than 100 eggs without success. Finally, in February 1944, she saw success after increasing the contact between the sperm and egg in the petri dish from 30 minutes to an hour—an accidental adjustment because she, an exhausted mother of an infant, had fallen asleep during the experiment.
A few days later, Menkin became the first person to see conception transpire outside the human body. She replicated this result three times over the next few months, and the duo published their findings. The paper caused “quite a stir in the scientific community,” according to an article from Arizona State University. The paradigm-shifting paper inspired further work on IVF, including experiments by obstetrician-gynecologist Landrum Shettles, who’s now recognized as a controversial pioneer in the field. Unfortunately, Menkin didn’t achieve the same level of fame as Rock, despite her continuing contributions to reproductive research.
Advances over the following decades led to the birth of the “first test tube baby,” Louise Brown, in July 1978.
In the early days of IVF, the technique only had single-digit success rates, but this has improved significantly due to more recent breakthroughs. For example, injecting a live sperm into the center of an egg can increase the odds of fertilization in cases of male infertility.
Today, people choose IVF for a variety of reasons, including challenges with infertility, or to avoid the risk of passing on a genetic condition. It’s also become increasingly popular among LGBT couples thanks to fewer legal hurdles and more social acceptance.
In fact, nearly a century after IVF was first achieved in the lab, scientists are still coming up with ways to boost its efficacy—including enlisting AI and robots. 
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Lead image: Rohane Hamilton / Shutterstock
