Look closely: this is history in the making. These are the clearest pictures ever taken of what is the starting point of every human life: ovulation occurring inside a woman’s body.

“The release of the oocyte from the ovary is a crucial event in human reproduction,” says Jacques Donnez at the Catholic University of Louvain (UCL) in Brussels, Belgium. “These pictures are clearly important to better understand the mechanism.”

Observing ovulation in humans is extremely rare, and previous images have been fuzzy. Donnez captured the …