Joy tells a compelling and true account of how three pioneering individuals were able to successfully produce the first child through IVF that was ever born, but the process may look slightly different to modern science. IVF, or In Vitro Fertilization, is the scientific method which allows doctors to extract an egg and sperm from suitable donors, create an embryo by combining the two outside the womb, and then implanting the fertilized egg back into the body in order to continue the pregnancy in utero.

https://screenrant.com/how-in-vitro-fertilization-works-process-joy/