Embryo Project Encyclopedia

Franklin William Stahl studied DNA replication, bacteriophages, and genetic recombination in the US during the mid-twentieth and early twenty-first centuries. With his colleague Matthew Meselson, Stahl performed an experiment called the Meselson-Stahl experiment, which provided evidence for a process called semi-conservative DNA replication. Semi-conservative replication is a process in which each strand of a parental DNA double helix serves as a template for newly replicated daughter strands, so that one parental strand is conserved in every daughter double helix. Those findings supported the Watson-Crick Model for DNA replication proposed in 1953 by James Watson and Francis Crick, convincing many biologists about DNA’s structure and replication in the 1950s. Stahl’s genetics research, especially that of DNA replication, showed researchers how genetic information is distributed within a cell and is passed down from cell to cell.

In April 1994, Elizabeth Raymond, Sven Cnattingius, and John Kiely published “Effects of Maternal Age, Parity, and Smoking on the Risk of Stillbirth” in the British Journal of Obstetrics and Gynecology, now known as BJOG: An International Journal of Obstetrics and Gynecology. The article examines how advanced maternal age, defined as delivery at thirty-five years old or older, cigarette smoking, and nulliparity, or the state of never having given birth, can negatively impact pregnancy. At the time of publication, according to Raymond and colleagues, stillbirths comprised over half of all perinatal, or close to birth, deaths and more than one-third of total fetal and infant deaths in Europe and North America. In the article, Raymond and her coauthors demonstrate how certain risk factors may increase the risk of stillbirth at different stages of pregnancy, which helped set a foundation for future research in interventions to prevent stillbirth.

In 2006, the United States Food and Drug Administration, or FDA, published the “Requirements on Content and Format of Labeling for Human Prescription Drug and Biological Products,” also called the Physician Labeling Rule, to improve the safety and efficacy of prescription drugs and drug products. Within the Physician Labeling Rule, the FDA includes a section titled “Use in Specific Populations” or Section 8, which refers to drugs used by pregnant women, lactating women, and people of reproductive capacity. The FDA stated that the purpose of the Physician Labeling Rule was to make drug labels easier for physicians to understand and use when prescribing drugs to pregnant women. With the Physician Labeling Rule, the FDA improved patient-physician communication and the safety of drug use during pregnancy.

In 1987, the World Health Organization, or WHO, took action to improve the quality of maternal health around the world through the declaration of the Safe Motherhood Initiative, or the SMI, at an international conference concerning maternal mortality in Nairobi, Kenya. Initially, the SMI aimed to reduce the prevalence of maternal mortality around the world, as over 500,000 women died during pregnancy and childbirth annually at the time of its inception, while about 98 percent of those deaths occurred in low-income countries. While WHO led the initiative, many organizations in various countries participated in additional programs in order to implement the goals of the SMI. WHO developed the SMI in order to reduce the prevalence of maternal death, developing one of the first proposals that brought attention to maternal health on a global basis at a time when global maternal mortality was high.

Jesse Bennett, sometimes spelled Bennet, practiced medicine in the US during the late eighteenth century and performed one of the first successful cesarean operations, later called cesarean sections, in 1794. Following complications during his wife’s childbirth, Bennett made an incision through her lower abdomen and uterus to deliver their infant. Bennett’s biographers report that his operation was the first cesarean section where both the pregnant woman and the infant survived. Previously, physicians used cesarean sections to save the fetus from a pregnant woman who had already died during childbirth. Bennett successfully performed a cesarean section, a procedure used worldwide in the twenty-first century when a vaginal delivery is not possible or would pose a risk to the woman or fetus.

In 1999, the Inter-agency Working Group on Reproductive Health in Crises, hereafter the IAWG, wrote the Minimum Initial Services Package, hereafter MISP, which is the second chapter in Reproductive Health in Refugee Situations: An Inter-agency Field Manual. The IAWG wrote MISP for governments and agencies, who respond to humanitarian crises, as a guide for the provision of reproductive health services at the beginning of a humanitarian crises. The goal of MISP was to outline the services that people in humanitarian crises are to receive to minimize injury and death from complications related to reproductive health, prevent and manage the consequences of sexual violence, and reduce the transmission of sexually transmitted infections, or STIs. MISP recognizes that reproductive health is a human right and applies to people in humanitarian crises, providing specific details for governments and agencies to follow and mitigate the adverse effects of reproductive health issues in vulnerable populations.

Breast augmentation involves the use of implants or fat tissue to increase patient breast size. As of 2019, breast augmentation is the most popular surgical cosmetic procedure in the United States, with annual patient numbers increasing by 41 percent since the year 2000. Since the first documented breast augmentation by surgeon Vincenz Czerny in 1895, and later the invention of the silicone breast implant in 1963, surgeons have developed the procedure into its own specialized field of surgery, creating various operating techniques for different results. By having varied incisions, implant placements, and improved ways of treating surgery-related complications, advanced technology has enabled women to undergo breast augmentations for aesthetic, medical, or reconstructive reasons. Trans women may also benefit from breast augmentations. Having the option of a breast augmentation gives women more control over their physical appearance, which may improve their self-image and boost their confidence.

In the 1960s, two plastic surgeons from the United States, Thomas Dillon Cronin and Frank Judson Gerow, collaborated with the Dow Corning Corporation, which specialized in silicone products, to create the first silicone breast implant. Surgeons used the implant, named the Cronin-Gerow implant, to improve the look of a woman’s breasts, by correcting for asymmetry, augmenting the size, or creating a more uplifted profile. Surgeons began widely using the breast implant almost immediately after it reached the US market in 1964, and breast augmentation quickly became one of the most popular cosmetic surgeries in the country. The creation of a silicone breast implant not only established a new branch of cosmetic surgery, but it also enabled women with breast cancer to receive reconstructions to improve their aesthetic appearance after cancer treatment and removal of the cancerous breast tissues.

In May 1953, scientists James Watson and Francis Crick wrote the article “Genetical Implications of the Structure of Deoxyribonucleic Acid,” hereafter “Genetical Implications,” which was published in the journal Nature. In “Genetical Implications,” Watson and Crick suggest a possible explanation for deoxyribonucleic acid, or DNA, replication based on a structure of DNA they proposed prior to writing “Genetical Implications.” Watson and Crick proposed their theory about DNA replication at a time when scientists had recently reached the consensus that DNA contained genes, which scientists understood to carry information that determines an organism’s identity. Watson and Crick’s replication mechanism as presented in “Genetical Implications” contributed to the two scientists sharing a portion of the 1962 Nobel Prize in Physiology or Medicine. With their suggested DNA replication mechanism in “Genetical Implications,” Watson and Crick explained how genes are copied and passed along to new cells and organisms, thereby explaining how the information contained within genes is preserved through generations.