Hermann Joseph Muller conducted three experiments in 1926 and 1927 that demonstrated that exposure to x-rays, a form of high-energy radiation, can cause genetic mutations, changes to an organism's genome, particularly in egg and sperm cells. In his experiments, Muller exposed fruit flies (Drosophila) to x-rays, mated the flies, and observed the number of mutations in the offspring. In 1927, Muller described the results of his experiments in "Artificial Transmutation of the Gene" and "The Problem of Genic Modification". His discovery indicated the causes of mutation and for that research he later received the Nobel Prize in Physiology or Medicine in 1946. Muller's experiments with x-rays established that x-rays mutated genes and that egg and sperm cells are especially susceptible to such genetic mutations.

In the US during the late 1960s, Stanley Alan Plotkin, John D. Farquhar, Michael Katz, and Fritz Buser isolated a strain of the infectious disease rubella and developed a rubella vaccine with a weakened, or attenuated, version of the virus strain. Rubella, also called German measles, is a highly contagious disease caused by the rubella virus that generally causes mild rashes and fever. However, in pregnant women, rubella infections can lead to developmental defects in their fetuses. Plotkin and his collaborators weakened a strain of rubella, called RA 27/3, by growing the virus in WI-38 cells, a strain of human embryonic cells developed at the Wistar Institute by Leonard Hayflick in the early 1960s. Their research led to the development of a rubella vaccine, which prevented rubella in children and congenital rubella syndrome in the fetuses of pregnant women who had contracted rubella.

David Wildt's cheetah (Acinonyx jubatus) research from 1978-1983 became the foundation for the use of embryological techniques in endangered species breeding programs. The cheetah is a member of the cat family (Felidae), which includes thirty-seven species. According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) all Felidae species are currently threatened or endangered, with the exception of the domestic cat (Felinus catus). Cheetahs are an internationally recognized charismatic megafauna species, prized zoo specimens, difficult to breed, and the basis of many conservation campaigns. Like most species, cheetahs have not traditionally been studied; only a few "model" organisms have been thoroughly researched in a laboratory setting. This research revealed that the difficulty observed in breeding cheetahs in captivity is due to their lack of genetic diversity.

In 2003, molecular biology and genetics researchers Coleen T. Murphy, Steven A. McCarroll, Cornelia I. Bargmann, Andrew Fraser, Ravi S. Kamath, Julie Ahringer, Hao Li, and Cynthia Kenyon conducted an experiment that investigated the cellular aging in, Caenorhabditis elegans (C. elegans) nematodes. The researchers investigated the interactions between the transcription factor DAF-16 and the genes that regulate the production of an insulin-like growth factor 1 (IGF-1-like) protein related to the development, reproduction, and aging in C. elegans. Transcription factors, like DAF-16, are proteins that regulate the transcription of deoxyribonucleic acid (DNA) into messenger ribonucleic acid (mRNA), which later determines which proteins the cell produces. The research team's experiment suggested that an increase in the activity of the DAF-16 protein decreases the transcription of the genes that regulate the production of IGF-1-like proteins, increasing lifespan in nematodes. The team published their results in the article 'Genes that act downstream of DAF-16 to influence the lifespan of Caenorhabditis elegans' in Nature in June 2003. By comparing the regulation of gene expression in C. elegans with similar genes and pathways in humans, Murphy's research team sought to better understand cellular function and aging in humans.

In 1998 and 1999, Teraporn Vutyavanich, Theerajana Kraisarin, and Rung-Aroon Ruangsri in Thailand showed that ginger alleviated nausea in pregnant women. Vutyavanich and his colleagues found that the group of pregnant women who took ginger capsules reported significantly fewer nausea symptoms and vomiting episodes than the group who only received the placebo. Vutyavanich and his team’s study at Chiang Mai University in Chiang Mai, Thailand, was one of the earliest to investigate and support the use of ginger as an effective treatment for relieving pregnancy-related nausea and vomiting.

In 1968, pediatric researchers Jerold Lucey, Mario Ferreiro, and Jean Hewitt conducted an experimental trial that determined that exposure to light effectively treated jaundice in premature infants. The three researchers published their results in 'Prevention of Hyperbilirubinemia of Prematurity by Phototherapy' that same year in Pediatrics. Jaundice is the yellowing of the skin and eyes due to the failure of the liver to break down excess bilirubin in the blood, a condition called hyperbilirubinemia. Bilirubin is a product that results from the degradation of red blood cells, which the immature liver of premature infants often has difficulty breaking down. Lucey's group's study demonstrated both the efficacy of phototherapy, which uses light to breakdown the bilirubin in the blood, as treatment for hyperbilirubinemia. As a result of Lucey's research team's study, physicians adopted phototherapy as the standard of care for treating premature infants born with jaundice.

In 2004, Shu-Shya Heh, Lindsey Coombes, and Helen Bartlett studied the association between Chinese postpartum (post-childbirth) practices and postpartum depression in Taiwanese women. The researchers surveyed Taiwanese women about the social support they received after giving birth and then evaluated the depression rates in the same women. Heh and her colleagues focused on the month following childbirth, which according to traditional Chinese medicine, is an important period that warrants a set of specialized practices to aid the woman's recovery. Collectively called zuoyuezi (doing the month), the postpartum practices require the help of someone else, typically the woman's mother or mother-in-law, to complete. Heh and her colleagues found that generally, Taiwanese women with more social support displayed fewer postpartum depressive symptoms, and concluded that the practice of doing the month helped prevent postpartum depression in Taiwanese women.

In 1931, physician Lucy Wills conducted a study of nutritional deficiencies that caused anemia in pregnant women in Bombay, India, later renamed Mumbai. Anemia is a lack of healthy red blood cells in the blood. Wills published the results of her study in the medical article 'Treatment of ‘Pernicious Anaemia of Pregnancy' and 'Tropical Anaemia'' in the British Medical Journal in 1931. Wills's research contributed to knowledge of anemia and the possible causes associated with the disease, such as the symptoms of fatigue and irritability. Wills attempted to connect the association of B vitamins and anemia. Wills's findings influenced scientists to research the importance of folic acid, one of the B group vitamins, and the role it plays in the development of a fetus and in women's health.

From 1958 to 1961, Leonard Hayflick and Paul Moorhead in the US developed a way in the laboratory to cultivate strains of human cells with complete sets of chromosomes. Previously, scientists could not sustain cell cultures with cells that had two complete sets of chromosomes like normal human cells (diploid). As a result, scientists struggled to study human cell biology because there was not a reliable source of cells that represented diploid human cells. In their experiments, Hayflick and Moorhead created lasting strains of human cells that retained both complete sets of chromosomes. They then froze samples from the cultures so that the cells remained viable for future research. They also noted that cells could divide only a certain number of times before they degraded and died, a phenomenon later called the Hayflick limit. Hayflick and Moorhead’s experiment enabled research on developmental biology and vaccines that relied on human cell strains.

Advanced Cell Technology (ACT), a stem cell biotechnology company in Worcester, Massachusetts, showed the potential for cloning to contribute to conservation efforts. In 2000 ACT researchers in the United States cloned a gaur (Bos gaurus), an Asian ox with a then declining wild population. The researchers used cryopreserved gaur skin cells combined with an embryo of a domestic cow (Bos taurus). A domestic cow also served as the surrogate for the developing gaur clone. The successful procedure opened the opportunity to clone individuals from species for which there are few or zero live specimens. The official release of this experiment's data was published in the paper 'Cloning of an Endangered Species (Bos gaurus) Using Interspecies Nuclear Transfer,' in October 2000. In the article, the researchers presented data collected from several cloned fetuses that were aborted before the full term of 283 days. At the time of publication, the gaur bull fetus, named Noah at birth, had developed for greater than 180 days. Noah was born on 8 January 2001, but died two days later due to dysentery. The development, birth, and death of Noah became a platform for conservationists and ethicists to critique the role of cloning in society and as a method to conserve species.