Embryo Project Encyclopedia

The male body, followed by male reproductive organs from which the sperm originates, is depicted from top to bottom at the left. Under the male reproductive organs is a diagram of a single sperm. To the right of the sperm diagram, the physiological and morphological changes a sperm undergoes to fertilize an egg are depicted from left to right. Each change is associated with a light pink rectangle background. Each light pink rectangle corresponds to the location of the sperm within the female reproductive organs, which is depicted above it. In addition, a molecular view of each change is directly under each light pink rectangle.
It is important to note the background color of the illustration. A blue to purple gradient depicts the two phases of sperm capacitation: sperm capacitation is in blue, and the acrosome reaction is in purple. It is still unclear where the two phases differentiate and thus a gradient is used as opposed to two distinct colors. The title location for each phase designates the approximate start of each phase.

In June 2015, the Ethics Committee of the American Society for Reproductive Medicine, or ASRM, published “Use of reproductive technology for sex selection for nonmedical reasons” in Fertility and Sterility. In the report, the Committee presents arguments for and against the use of reproductive technology for sex selection for any reason besides avoiding sex-linked disorders, or genetic disorders that only affect a particular sex. When couples have no family history of a sex-linked disease, the use of reproductive technology for sex selection raises ethical questions about the application of sex selection technology to fulfill parental desires. “Use of reproductive technology for sex selection for nonmedical purposes” examines the ethical debate surrounding sex selection for nonmedical purposes and is an educational and ethical reference for physicians who are considering offering those services in their practices.

In February 1953, Linus Pauling and Robert Brainard Corey, two scientists working at the California Institute of Technology in Pasadena, California, proposed a structure for deoxyribonucleic acid, or DNA, in their article “A Proposed Structure for the Nucleic Acids,” henceforth “Nucleic Acids.” In the article, Pauling and Corey suggest a model for nucleic acids, including DNA, that consisted of three nucleic acid strands wound together in a triple helix. “Nucleic Acids” was published in Proceedings of the National Academy of Sciences shortly after scientists came to the consensus that genes, the biological factors that control how organisms develop, contained DNA. Though scientists proved Pauling and Corey’s model incorrect, “Nucleic Acids” helped scientists understand DNA’s structure and function as genetic material.

William Thomas Astbury studied the structures of fibrous materials, including fabrics, proteins, and deoxyribonucleic acid, or DNA, in England during the twentieth century. Astbury employed X-ray crystallography, a technique in which scientists use X-rays to learn about the molecular structures of materials. Astbury worked at a time when scientists had not yet identified DNA’s structure or function in genes, the genetic components responsible for how organisms develop and reproduce. He was one of the first scientists to use X-ray crystallography to study the structure of DNA. According to historians, Astbury helped establish the field of molecular biology as he connected microscopic changes in the structure of materials to changes in their large-scale properties. Astbury and his images helped scientists to understand the structure of DNA and its role in genetics.

In 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty published an article in which they concluded that genes, or molecules that dictate how organisms develop, are made of deoxyribonucleic acid, or DNA. The article is titled “Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types: Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III,” hereafter “Transformation.” The authors isolated, purified, and characterized genes within bacteria and found evidence that those genes were made of DNA and not protein. Though scientists were initially skeptical that genes were made of DNA, they later recognized that the data reported in “Transformation” were clear evidence that DNA was genetic material, a revelation that furthered research about how organisms grow, develop, and pass on traits to offspring.

In 2017, Julie Carré, Nicolas Gatimel, Jessika Moreau, Jean Parinaud, and Roger Léandri published “Does Air Pollution Play a Role in Infertility?: a Systematic Review,” hereafter “Does Air Pollution Play a Role,” in the journal Environmental Health. The authors completed a systematic literature review to investigate the effects of air pollutants on fertility in exposed populations. Since air quality has an impact on overall health as well as on reproductive function, the authors sought to increase the awareness of the importance of environmental protection issues among the general public and the authorities. The article “Does Air Pollution Play a Role” provided the foundation for further research on how air pollution can contribute to low reproductive capacity in areas with high exposure.

In September 2003, Robert L. Goldenberg and Cortney Thompson published the article “The Infectious Origins of Stillbirth” in the American Journal of Obstetrics and Gynecology. In the article, the authors conducted a literature review of articles from the US National Library of Medicine database to review the relationship between perinatal infections, which are infections around the time of birth, and the occurrence of stillbirth. Stillbirth is the death of a fetus in the uterus after at least twenty weeks of pregnancy. Infectious disease can cause or increase the risk of stillbirth in several ways, by causing illness in the pregnant person, damaging the placenta, or directly infecting the fetus. Infectious agents can be viruses, bacteria, or protozoa. Rates of infectious disease and stillbirth are both higher in developing than in developed countries, and the authors state that stillbirth due to infectious disease is also higher. “The Infectious Origins of Stillbirth” provides a comprehensive review of the information available on how infections can lead to stillbirth, providing a foundation for further research.

Carol Downer was a reproductive health and abortion rights activist in the twentieth and twenty-first centuries in the US and other countries. During the late 1960s, many women reported knowing little about female anatomy and receiving little information from their physicians. Downer advocated for women’s reproductive anatomy education and encouraged women to not rely on the intervention of a medical doctor for all reproductive issues. Downer demonstrated how to perform a vaginal self-examination to many women and taught women around the world how to provide safer in-home abortions when abortions were illegal. Downer helped start clinics throughout California which provided some of the first legal abortions in the US. With her reproductive health activism, Downer spread reproductive health self-help tactics throughout the US and the world, thereby improving women’s access to health information.