On July 25, 1978, Louise Joy Brown, the world’s first baby to be conceived via in vitro fertilization (IVF) is born at Oldham and District General Hospital in Manchester, England, to parents Lesley and Peter Brown. The healthy baby was delivered shortly before midnight by caesarean section and weighed in at five pounds, 12 ounces.

Before giving birth to Louise, Lesley Brown had suffered years of infertility due to blocked fallopian tubes. In November 1977, she underwent the then-experimental IVF procedure. A mature egg was removed from one of her ovaries and combined in a laboratory dish with her husband’s sperm to form an embryo. The embryo then was implanted into her uterus a few days later. Her IVF doctors, British gynecologist Patrick Steptoe and scientist Robert Edwards, had begun their pioneering collaboration a decade earlier. Once the media learned of the pregnancy, the Browns faced intense public scrutiny. Louise’s birth made headlines around the world and raised various legal and ethical questions.

The Browns had a second daughter, Natalie, several years later, also through IVF. In May 1999, Natalie became the first IVF baby to give birth to a child of her own. The child’s conception was natural, easing some concerns that female IVF babies would be unable to get pregnant naturally. In December 2006, Louise Brown, the original “test tube baby,” gave birth to a boy, Cameron John Mullinder, who also was conceived naturally.

Today, IVF is considered a mainstream medical treatment for infertility. Hundreds of thousands of children around the world have been conceived through the procedure, in some cases with donor eggs and sperm.