Theodor Boveri investigated the mechanisms of heredity. He developed the chromosomal theory of inheritance and the idea of chromosomal individuality. Boveri sought to provide a comprehensive explanation for the hereditary role and behavior of chromosomes. He hoped that his experiments would also help to distinguish the roles of the nucleus and the cytoplasm in embryogenesis. Boveri was particularly interested in how offspring are shaped by the attributes of their parents. His exhaustive studies of chromosomal and cellular behavior during early development paved the way for much of the emerging field of embryology.

Emma Wolverton, also known as Deborah Kallikak, lived her entire life in an institution in New Jersey after psychologist Henry Goddard classified her as feeble-minded. He also wrote a book about Wolverton and her family that psychiatrists previously used to show that intellectual disability is hereditary. At the time, researchers in the psychology field, including Goddard, were working to understand differences in people’s intellectual abilities. They used the term feeble-minded to refer to those they described as having lower intellectual functioning. While Wolverton spent nearly her entire life living and working in institutions for the feeble-minded, more recent investigations of her life show she was not what is now considered intellectually disabled. Wolverton’s involvement in Goddard’s research as Deborah Kallikak influenced twentieth century ideas around the heritability and treatment of those with disabilities.

Katharine Dexter McCormick, who contributed the majority of funding for the development of the oral contraceptive pill, was born to Josephine and Wirt Dexter on 27 August 1875 in Dexter, Michigan. After growing up in Chicago, Illinois, she attended the Massachusetts Institute of Technology (MIT), where she graduated in 1904 with a BS in biology. That same year, she married Stanley McCormick, the son of Cyrus McCormick, inventor and manufacturer of the mechanized reaper. Katharine's father was a prominent Chicago lawyer, so this marriage created the accumulation of great wealth and power. Her primary contribution to society was her commitment to reproductive reform.

Patrick Christopher Steptoe was a British gynecologist responsible for major advances in gynecology and reproductive technology. Throughout his career Steptoe promoted laparoscopy, a minimally invasive surgical technique that allows a view inside the abdominal cavity, successfully advancing its usefulness in gynecology. After partnering with embryologist Robert Edwards in 1966, the pair performed the first in vitro fertilization in humans.

Sir Graham Collingwood Liggins devoted much of his professional life to obstetric research. Liggins demonstrated that hormones created by the fetus helped initiate labor, rather than hormones originating solely from the mother. Liggins also discovered that cortisol given to pregnant mothers helped delay premature labor, and that it increased the likelihood that premature infants would breathe normally after birth. Prior to cortisol treatment, premature infants often died of respiratory distress syndrome characterized by the inability to inflate immature lungs. Before the clinical application of Liggins' discoveries in the 1980s, premature infants born before 32 weeks of gestation generally died because of respiratory distress.

Ina May Gaskin is a certified professional midwife, or CPM, in the US during the late twentieth and early twenty-first centuries. She worked at the Farm Midwifery Center in Summertown, Tennessee, a center well known for its low rates of intervention, which contributed to low rates of maternal and fetal mortality. One technique Gaskin used when assisting women with delivery helped resolve a complication called shoulder dystocia, which is when a part of the infant’s body is delivered, but the rest of the body is stuck in the birth canal. Her work served as an example for midwives and obstetricians, physicians who specialize in a woman’s reproductive system, childbirth, and pregnancy, to use a low-intervention approach without medication or a cesarean section. Through her work in developing different birthing techniques, Gaskin provided women with alternative ways to deliver infants without the need for hospitals, medication, or surgical intervention, even in the case of complicated births.

Gregory Goodwin Pincus, one of the original researchers responsible for the development of the first oral contraceptive pill, was born in Woodbine, New Jersey, on 19 April 1903 to Russian Jewish parents. In 1924 Pincus received his BS degree from Cornell University, and in 1927 he received his MS and PhD from Harvard University, having studied under William Ernest Castle and William John Crozier. After this, Pincus studied at Cambridge University with Francis Hugh Adam Marshall and John Hammond, both reproductive biologists, and at the Kaiser Wilhelm Institute with Richard Goldschmidt, a geneticist.

Landrum Brewer Shettles is remembered as an important contributor to early in vitro fertilization research in the United States as well as a prolific author on the subject of choosing a child's sex before conception. Shettles was born in Pontotoc County, Mississippi on 21 November 1909 to Sue Mounce and Brazil Manly. Shettles trained and worked as a gynecologist at Columbia University Presbyterian Medical Center, after receiving his MD in 1943 from Johns Hopkins University. While working at Columbia, Shettles conducted experiments dealing with egg fertilization and in vitro fertilization. From this work, Shettles published Ovum Humanum, a book containing detailed photographs of human eggs in development. Despite professional eccentricities and social ineptitude that, at times, hindered his work with colleagues, Shettles is considered a pioneer of in vitro fertilization technology as well as a major contributor to fertilization and embryonic research.

Robert Alan Good was an American physician and scientific researcher who explored the cellular mechanisms of immunity. His research and discoveries earned him the label of "father of modern immunology." Though his work in immunology is considered his greatest scientific achievement, Good is also well known for his work with tissue engineering. From his research on immunology, Good was able to perform the first successful allogeneic (donor and recipient are unrelated) bone marrow transplant. A bone marrow transplant is a form of hematopoietic stem cell transplant in which hematopoietic stem cells are infused into a patient to treat various diseases of the blood including some autoimmune and inherited conditions, and cancer. Following his success with bone marrow transplants, Good established a bone marrow transplantation program for children at the University of South Florida.

Charles Bonnet was a naturalist and philosopher in the mid eighteenth century. His most important contribution to embryology was the discovery of parthenogenesis in aphids, proving that asexual reproduction of offspring was possible. In his later life, he was an outspoken defender of the theory of generation now known as preformationism, which stated that offspring exist prior to conception preformed in the germ cell of one of their parents.

Subscribe to People