Wilhelm Roux was a nineteenth-century experimental embryologist who was best known for pioneering Entwicklungsmechanik, or developmental mechanics. Roux was born in Jena, Germany, on 9 June 1850, the only son of Clotilde Baumbach and a university fencing master, F. A. Wilhelm Ludwig Roux. Roux described himself as an aloof child, but when he was fourteen he cultivated a passion for science that was encouraged by the director at Oberrealschule in Meiningen. Roux attended the University of Jena in 1869, but his education was halted after the first year because of his service in the military during the Franco-Prussian War. When he returned from the war, he continued to take classes and was admitted into the University of Jena medical faculty. He passed his medical examination in 1877 and became a licensed doctor.

Hilde Proscholdt Mangold was a doctoral student at the Zoological Institute at the University of Freiburg in Freiburg, Germany, from 1920-1923. Mangold conducted research for her dissertation 'On the Induction of Embryonic Primordia by Implantation of Organizers from Different Species' ('Ueber Induktion von Embryonanlagen durch Implantation artfremder Organisatoren'), under the guidance of Hans Spemann, a professor of zoology at the University of Freiburg. The dissertation was the culmination of five experiments on three species of newt embryos, of the genus Triton (presently, Triturus), performed during the summers of 1921 and 1922, which resulted in a confirmation of Spemann's organizer concept. Spemann and Mangold published the dissertation in a 1924 edition of Roux's Archives for Microscopic Anatomy and Developmental Mechanics (Roux's Archiv fur Mikroskopische Anatomie und Entwicklungsmechanik)."

Rudolf Carl Virchow lived in nineteenth century Prussia, now Germany, and proposed that omnis cellula e cellula, which translates to each cell comes from another cell, and which became and fundamental concept for cell theory. He helped found two fields, cellular pathology and comparative pathology, and he contributed to many others. Ultimately Virchow argued that disease is caused by changes in normal cells, also known as cellular pathology.

Gavin de Beer was an English zoologist known for his contributions to evolution and embryology, in particular for showing the inadequacy of the germ layer theory as it was then proposed. He was born in London, England, on 1 November 1899, but was raised for his first thirteen years in France where his father worked for a telegraph company. He entered Magdalen College, Oxford, in 1917 but his studies were soon interrupted by World War I. After serving in the military, he returned to Oxford where he studied under Edwin Goodrich. He graduated in 1922 but stayed on as a fellow of Merton College and to teach in the Zoology Department. He was the Jenkinson Memorial Lecturer between 1926 and 1938.

The Dickey-Wicker Amendment is an amendment attached to the appropriations bills for the Departments of Health and Human Services, Labor, and Education each year since 1996 restricting the use of federal funds for creating, destroying, or knowingly injuring human embryos. The Dickey-Wicker Amendment began as a rider (another name for an amendment) attached to House Resolution (H.R.) 2880. H.R. 2880 was a 1996 appropriations bill sponsored by the head of the House Appropriations Committee, Republican Representative Bob Livingston of Louisiana, for the Department of Health and Human Services titled "The Balanced Budget Downpayment Act, I." Though the appropriations bill's sole sponsor was Representative Livingston, the amendment itself is named for its authors: Representative Jay Dickey, a Republican from Arkansas, and Roger Wicker, a Republican from Mississippi.

Leo Loeb developed an experimental approach to studying cancer and pioneered techniques for tissue culture and in vitro tissue transplantation which impacted early-to-mid twentieth century experimental embryology. Loeb received his medical degree from the University of Zurich in 1897. As part of his doctorate, he completed a thesis on the outcomes of tissue transplantation in guinea pigs. Loeb's thesis inspired a life-long interest in tissue transplantation. His research culminated in greater than 400 publications, including a book called The Biological Basis of Individuality, in which he demonstrated the potential immortality of certain mammalian tissues.

Wilhelm Roux was an influential figure in the early history of experimental embryology. Although he originally studied medicine, he was invited to be a Privatdozentur, or unsalaried lecturer, at the Anatomical Institute in Breslau (Wroclaw), Poland, in 1879. He spent the next ten years at this institute, working his way from Dozent to associate professor and finally, in 1889, to director for his own institute, Institut für Entwicklungsgeschichte, or Institute for Developmental History and Mechanics. It was here that he performed what is perhaps his most famous series of experiments on green frog eggs in 1888 and published in Virchows Archiv, which he titled "Beiträge zur Entwicklungsmechanik des Embryo. Über die künstliche Hervorbringung halber Embryonen durch Zerstörung einer der beiden ersten Furchungskugeln, sowie über die Nachentwickelung (Postgeneration) der fehlenden Körperhälfte."

Hans Adolf Eduard Driesch was a late-nineteenth and early-twentieth century philosopher and developmental biologist. In the spring of 1891 Driesch performed experiments using two-celled sea urchin embryos, the results of which challenged the then-accepted understanding of embryo development. Driesch showed that the cells of an early embryo, when separated, could each continue to develop into normal larval forms. This finding contrasted with Wilhelm Roux's experiments with frog eggs from which Roux concluded that embryonic cells have predetermined fates - they cannot form into one thing when separated, and a different form when left unseparated. To Roux, embryos were made up of a mosaic of cells, all of which were important and necessary for the viable embryos to form. Driesch, on the other hand, was able to show that individual cells resulting from cleavage of the fertilized egg were all able to form into viable embryos, and not just predetermined parts that Roux believed.

In the United States, the Code of Federal Regulations Title 45: Public Welfare, part 46 (45 CFR 46) provides protection for human subjects in research carried out or supported by most federal departments and agencies. 45 CFR 46 created a common federal policy for the protection of such human subjects that was accepted by the Office of Science and Technology Policy and issued by each of the departments and agencies listed in the document. The code is divided into four subparts: basic protection applicable to all human research subjects; additional protections for women, human fetuses, and neonates; additional protections for prisoners; and additional protections for children. Although 45 CFR 46 contains additional protections for human fetuses, it is important to note that these protections last only from implantation to birth, and are not extended to embryos before implantation.

Otto Mangold was an early twentieth century embryologist who specialized in the development of amphibian embryos. A major emphasis of his research was refining the concept of the organizer, now referred to as embryonic induction. He was born on 4 November 1891 in Auenstein, Germany, and came from what Viktor Hamburger, a colleague and personal acquaintance, described as "peasant stock." Mangold attended several universities including Tübingen, Freiburg, and Rostock. He was one of Hans Spemann's first students at Rostock before Mangold had to leave to serve in the air force in World War I.