It was a stunning little book, with the first clear pictures of human eggs in their earliest stages of development, and Ovum Humanum marked an important landmark in the growing knowledge of the human fertilization process.

Understanding Fertilization
For centuries, the reproductive process had been a mystery; people knew that intercourse was required to make a baby, but had little idea exactly how the baby came to be. That began to change in 1827, when scientists first learned that the female body contained eggs, known as ova. In 1843 scientists discovered that conception resulted from male sperm entering the egg, and in 1875 it was conclusively determined that human life sprung from a union of the two. Still, researchers were unsure when in a woman’s monthly cycle she was most likely to get pregnant; they incorrectly assumed that human cycles were similar to those of other mammals, with ovulation occurring at menstruation. Greater understanding came with the identification of the ovarian hormone progesterone, which plays a key role in pregnancy, in 1928; a year later the sex hormone estrogen was isolated. The stage was set for a closer examination of the fertilization process. In 1934 Harvard scientist Gregory Pincus conducted in vitro fertilization (IVF) experiments involving rabbits, and in 1944 John Rock and Miriam Menkin managed the first successful in vitro fertilization of a human egg.

The First Atlas of the Human Egg
Both Pincus and Menkin photographed the results of their experiments, but the photos were few and of low quality. Landrum Shettles, a New York doctor and IVF pioneer, took photographing the human egg to the next level. His photographic atlas of the human egg, Ovum Humanum was published in 1960. The book, intended for an academic and medical audience, contained a selection of the more than 1,000 photographs Shettles had taken over six years at Columbia-Presbyterian Hospital where he worked. Shettles worked with a Leica camera rigged to take pictures of a microscope slide, and he proved to be quite skilled as a photographer. He documented eggs from their earliest stage of development as oocytes through fertilization.

The Impact of Shettles’ Photos
For many readers, these color photographs were the first clear pictures of human eggs that they had ever viewed. Their publication marked an important step towards greater understanding of the earliest stages of life, stages that had previously been assumed but never seen. They were, in the words of Columbia doctor Georgianna Jagiello, “really thrilling photographs,” and interest in them extended far beyond Shettles’ fellow physicians. Photographs from Ovum Humanum appeared in several science textbooks and even the 1963 Catholic Youth Encyclopedia, which was ironic because the Catholic Church would come to condemn IVF in later years.

More Books, More Research
Ovum Humanum was not Shettles’ last book; in the early 1970s he co-authored the best-selling From Conception to Birth: The Drama of Life’s Beginning, which had more than a dozen printings; and Your Baby’s Sex: Now You Can Choose, which sold over a million copies. But selling books and taking pictures was one thing; making actual progress in the IVF field was another. Shettles would later say that in 1962 he had implanted a fertilized egg back into a woman, resulting in a successful implantation, but the claim was never substantiated, and his best-known attempt, involving Doris and John Del-Zio in 1973, ended in failure. Meanwhile, the English team of Robert Edwards and Patrick Steptoe was working away, careful and methodical in ways that Shettles was not. Theirs would be the greater triumph: the birth of the world’s first test tube baby in 1978.