Frederik Ruysch's cabinet of curiosities, commonly referred to simply as the Cabinet, was a museum Ruysch created in the Netherlands in the late 160ss. The Cabinet filled a series of small houses that Ruysch rented in Amsterdam and contained over 2,000 specimens, including preserved fetuses and infants. The collection remained in Amsterdam until it was purchased by Tsar Peter the Great of Russia in 1717 and transferred to St. Petersburg, Russia. Similar to Gunther von Hagens' twenty-first century Body Worlds exhibition, which presents bodies preserved through plastination, the Cabinet was open to both medical professionals and laypeople. The pieces in the Cabinet were life-like and aesthetically pleasing, making them valuable education tools for prenatal and infant anatomy as well as an effective way of garnering public interest in anatomy.

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.

As mice embryos develop, they undergo a stage of development called gastrulation. The hallmark of vertebrate gastrulation is the reorganization of the inner cell mass (ICM) into the three germ layers: ectoderm, mesoderm, and endoderm. Mammalian embryogenesis occurs within organisms; therefore, gastrulation was originally described in species with easily observable embryos. For example, the African clawed frog (Xenopus laevis) is the most widely used organism to study gastrulation because the large embryos develop inside a translucent membrane. Domestic chicken (Gallus gallus) gastrulation was also an early model organism because researchers could open the egg during development to look inside. Despite the challenges associated with studying mammalian gastrulation, the common house mouse (Mus musculus) has helped to shed light on the unique adaptations associated with mammalian development, and on the subtle differences in structure that give rise to significant divergence in late embryogenesis.

In an effort to develop tissue culture techniques for long-term tissue cultivation, French surgeon and biologist Alexis Carrel, and his associates, produced and maintained a series of chick heart tissue cultures at the Rockefeller Institute in New York City. From 1912 to 1946, this series of chick heart tissue cultures remained alive and dividing. Since the duration of this culture greatly exceeded the normal chick life span, the cells were deemed immortal. Although this conclusion was challenged by further experiments in the 1960s, the publicity surrounding the immortal chick heart tissue significantly influenced the concept of cell immortality and cellular aging from the 1920s through the 1960s. Carrel's experiment convinced many biologists to accept immortality as an intrinsic property of all cells, not just the cell line through which genetic material is passed to offspring, called the germ line. Consequently, the phenomenon of cellular aging was regarded not as an intrinsic characteristic, but was attributed to external factors such as the accumulation of waste products within the cell.

Mesenchyme is a type of animal tissue comprised of loose cells embedded in a mesh of proteins and fluid, called the extracellular matrix. The loose, fluid nature of mesenchyme allows its cells to migrate easily and play a crucial role in the origin and development of morphological structures during the embryonic and fetal stages of animal life. Mesenchyme directly gives rise to most of the body's connective tissues, from bones and cartilage to the lymphatic and circulatory systems. Furthermore, the interactions between mesenchyme and another tissue type, epithelium, help to form nearly every organ in the body.

Eduard Friedrich Wilhelm Pflüger was a physiologist known for his research on respiration, the respiratory quotient, experimenting on the effects of electricity on muscles and nerves, and his study of the ovaries and egg development. His experiments on how the gravitational orientation of frog eggs affects their cleavage plane inspired embryologists such as Wilhelm Roux and Gustav Born to conduct their own experiments using frog eggs.

Frederik Ruysch made anatomical drawings and collected and preserved human specimens, many of which were infants and fetuses, in the Netherlands during the seventeenth and eighteenth centuries. Ruysch had many interests, including anatomy, botany, and medicine, and he discovered structures of the lymphatic system and of the eye. His collection of preserved human specimens were used as educational tools for his students and for other physicians, and they were displayed in a museum of his own making that was open to the public.

In 2002 Eric Davidson and his research team published 'A Genomic Regulatory Network for Development' in Science. The authors present the first experimental verification and systemic description of a gene regulatory network. This publication represents the culmination of greater than thirty years of work on gene regulation that began in 1969 with 'A Gene Regulatory Network for Development: A Theory' by Roy Britten and Davidson. The modeling of a large number of interactions in a gene network had not been achieved before. Furthermore, this model revealed behaviors of the gene networks that could only be observed at the levels of biological organization above that of the gene.

Johann Friedrich Meckel studied abnormal animal and human anatomy in nineteenth century Germany in an attempt to explain embryological development. During Meckel's lifetime he catalogued embryonic malformations in multiple treatises. Meckel's focus on malformations led him to develop concepts like primary and secondary malformations, atavism, and recapitulation- all of which influenced the fields of medicine and embryology during the nineteenth and twentieth centuries.

In 2008 researchers Daniel Warner and Richard Shine tested the Charnov-Bull model by conducting experiments on the Jacky dragon (Amphibolurus muricatus), in Australia. Their results showed that temperature-dependent sex determination(TSD) evolved in this species as an adaptation to fluctuating environmental temperatures. The Charnov-Bull model, proposed by Eric Charnov and James Bull in 1977, described the evolution of TSD, although the model was, for many years, untested. Many reptiles and some fish exhibit non-genetic sex determination, in which an embryos' environment can influence the sex of the adult organism. Environmental conditions such as humidity or population density can alter sex in some organisms, and a widespread form of non-genetic sex determination is temperature-dependent sex determination. TSD reveals how embryonic development can contribute to the evolution of physiological processes. Researchers have documented TSD in a wide range of species, and they continue to investigate how such a sex determining system has evolved.