In 2006, the article “HPV in the Etiology of Human Cancer,” hereafter “HPV and Etiology,” by Nubia Muñoz, Xavier Castellsagué, Amy Berrington de González, and Lutz Gissmann, appeared as the first chapter in the twenty-fourth volume of the journal Vaccine. Muñoz and colleagues discuss the role of the Human Papillomavirus, or HPV, in uterine cervical cancers. The authors introduce the mechanisms of HPV infection that lead to genital and non-genital cancers, establishing a link between HPV and multiple human cancers. The authors end by mentioning how other factors, such as pregnancy, smoking, and age, can influence HPV progressing into cervical cancer, which can be fatal. In the article, Muñoz and colleagues use meta-analyses of case studies and clinical trials to show which specific types of HPV are linked to cervical and other human cancers and the impacts of cofactors on the development of those cancers.

In the United States, most people are assigned both a biological sex and gender at birth based on their chromosomes and reproductive organs. However, there is an important distinction between biological sex and gender. Biological sex, such as male or female, commonly refers to physical characteristics. Gender refers to the socially constructed roles, behaviors, and actions people take on, usually in relation to expectations of masculinity or femininity. As of 2022, there is disagreement over the relation between sex and gender. People’s biological sex and gender greatly influence the way they understand themselves, as well as how others treat them and how they interact with society. Moreover, some people’s gender differs from what they were assigned at birth, and they face discrimination, harassment, and violence. Evolving understandings of gender and sex in the US have created more ways for people to live and express their gender identities.

In the second half of the twentieth century, scientists learned how to clone organisms in some species of mammals. Scientists have applied somatic cell nuclear transfer to clone human and mammalian embryos as a means to produce stem cells for laboratory and medical use. Somatic cell nuclear transfer (SCNT) is a technology applied in cloning, stem cell research and regenerative medicine. Somatic cells are cells that have gone through the differentiation process and are not germ cells. Somatic cells donate their nuclei, which scientists transplant into eggs after removing their nucleuses (enucleated eggs). Therefore, in SCNT, scientists replace the nucleus in an egg cell with the nucleus from a somatic cell.

Pearl Luella Kendrick researched prevention for pertussis, commonly known as whooping cough, in Grand Rapids, Michigan, during the mid-1900s. Pertussis is a respiratory disease that mainly affects infants and young children. During the 1920s, pertussis was responsible for more deaths in children in the United States than any other disease. In the 1930s, Kendrick created one of the first pertussis vaccines that underwent large-scale clinical trials. Towards the end of her career, Kendrick helped developed combination vaccines for other common childhood diseases at the time, including diphtheria, tetanus, pertussis, and poliomyelitis. She also studied immune responses in infants whose mothers had pertussis antibodies that transferred to them during pregnancy. Kendrick helped lower the incidence and death rate of pertussis and other common childhood diseases in the US through the creation of vaccines.

In 1950, physician and researcher Ernst Gräfenberg published “The Role of Urethra in Female Orgasm,” in the International Journal of Sexology. The article was one of the first to mention the area in the anterior, or front, vaginal wall colloquially called the G-spot. In the article, Gräfenberg acknowledges that many females experience problems related to sexual satisfaction, and he argues that researchers and physicians of the time did not know enough information about the anatomical mechanisms and localization of the female orgasm to help them. He claims that there is a distinct zone in the anterior vaginal wall along the urethra that plays a critical role in female sexual pleasure, making it important for physicians to consider when treating females’ sexual problems. Though researchers are still debating the structural existence of the G-spot as of 2022, “The Role of Urethra in Female Orgasm” was one of the first publications to explore the anatomical elements of the female orgasm, and it led to further research about female sexuality that has helped many individuals to better understand female pleasure.

Luc Montagnier studied viruses, the immune system, and cancer in France during the second half of the twentieth century. In his early career, Montagnier studied how cancer-causing viruses replicate and infect host cells. He received the Nobel Prize in Physiology or Medicine in 2008 for his team’s discovery that a retrovirus, human immunodeficiency virus, or HIV, was the cause of acquired immunodeficiency syndrome, or AIDS. AIDS is a chronic condition that results from HIV infection and damages the immune system. People who have AIDS typically experience increased vulnerability to a variety of diseases. Before Montagnier’s research on the virus, the exact cause of AIDS remained unknown to researchers and healthcare professionals. Beyond discovering HIV as the cause of AIDS, Montagnier’s work advanced a general understanding of how viral infection affects the immune system of the host organism.

Turtle morphology is unlike that of any other vertebrate. The uniqueness of the turtle's bodyplan is attributed to the manner in which the turtle's ribs are ensnared within its hard upper shell. The exact embryological and genetic mechanisms underpinning this peculiar anatomical structure are still a matter of debate, but biologists agree that the evolution of the turtle shell lies in the embryonic development of the turtle.

Two main elements characterize the skeletal morphology of turtles: the carapace and the plastron. For a turtle, the carapacial ridge begins in the embryo as a bulge posterior to the limbs but on both sides of the body. Such outgrowths are the first indication of shell development in turtle embryos. While the exact mechanisms underpinning the formation of the carapacial ridge are still not entirely known, some biologists argue that understanding these embryonic mechanisms is pivotal to explaining both the development of turtles and their evolutionary history.

This video is composed of a sequence of films created by John Tyler Bonner in the 1940s to show the life cycle of the cellular slime mold Dictyostelium discoideum. As only the second person to study slime molds, Bonner frequently encountered audiences who had never heard of, let alone seen, the unusual organism. He therefore decided to create a film to present at seminars in order to introduce his object of study; the time-lapsed film captivated audiences, indeed Bonner has described that the film "always stole the show." Bonner began working in the biology department at Princeton University in 1947, and although Princeton appears in the opening title, Bonner actually made the film for his senior thesis as an undergraduate at Harvard University with some early assistance from Frank Smith, a photographer. Although unsure of name of the device that was used for filming, he has described it as "the most amazing antique contraption that belonged to my professor, Wm. H. Weston. It consisted of a gigantic and VERY heavy set of brass gears that had numerous possible speeds that turned a crank on the side of an old 16 mm box camera that pointed into the ocular of a microscope. The electric motor that propelled it made such vibrations that the whole apparatus had to be on a separate table and not touching the microscope."

In 1893, Julia Barlow Platt published her research on the origins of cartilage in the developing head of the common mudpuppy (Necturus maculosus) embryo. The mudpuppy is an aquatic salamander commonly used by embryologists because its large embryonic cells and nuclei are easy to see. Platt followed the paths of cells in developing mudpuppy embryos to see how embryonic cells migrated during the formation of the head. With her research, Platt challenged then current theories about germ layers, the types of cells in an early embryo that develop into adult cells. In most organisms' development, three types of germ layers are responsible for the formation of tissues and organs. The outermost layer is called ectoderm, the middle layer mesoderm, and the innermost layer endoderm, although Platt called it entoderm. Platt's research provided a basis for scientists to clarify the destination or function of the germ layers in vertebrates' development.