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.

The "Humanae Vitae," meaning "Of Human Life" and subtitled "On the Regulation of Birth," was an encyclical promulgated in Rome, Italy, on 25 July 1968 by Pope Paul VI. This encyclical defended and reiterated the Roman Catholic Church's stance on family planning and reproductive issues such as abortion, sterilization, and contraception. The document continues to have a controversial reputation today, as its statements regarding birth control strike many Catholics as unreasonable.

Karl Wilhelm Theodor Richard von Hertwig is an important figure in the history of embryology for his contributions of artificial hybridization of sea urchin eggs and the formulation of his coelom theory. He was born 23 September 1850 in Friedelberg, Germany, to Elise Trapp and Carl Hertwig. Richard and his older brother Oscar began their studies at Jena under the direction of Ernst Haeckel from 1868 to 1871. In 1872 Hertwig became a lecturer in zoology at Jena while Oscar lectured in anatomy and embryology. As both brothers advanced in their respective fields, Hertwig left Jena to become a professor at Königsberg. In 1883 he was professor at Bonn and in 1885 in Munich, where he stayed until his retirement in 1925. Hertwig married Julia Braun in 1887 and had two sons and one daughter. He remained very active his entire life, outliving his brother Oscar by fifteen years.

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.

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.

The first successful cloning of a gaur in 2000 by Advanced Cell Technology involved the cells of two animals: an egg cell from a domestic cow and a skin cell from a gaur. The researchers extracted the egg cell from the ovary of the domestic cow and the skin cell from the skin of the gaur. First, the researchers performed nuclear transplantation on the egg cell of the cow, during which they removed the nucleus of the egg cell. The mitochondria of the egg cell remained intact inside the cell. Next, the researchers fused the egg cell of the cow and the skin cell of the gaur by applying a single electric pulse. That process resulted in a cellular complex that contained the nucleus from the gaur and the mitochondria from the cow. That cellular complex was then placed into the uterus of a different domestic cow. Once the cellular complex developed into a Day 46 fetus, researchers conducted morphological and genetic tests. The fetus then further developed into a gaur calf, which lived for forty-eight hours after birth.

On 15 April 1999, physician Gillian Thomas published the editorial “Improved Treatment for Cervical Cancer – Concurrent Chemotherapy and Radiotherapy,” henceforth “Improved Treatment,” in The New England Journal of Medicine. In that editorial, she discusses the potential benefits of combining chemotherapy drugs with radiation to treat women with cervical cancer. At the time, healthcare professionals rarely treated cervical cancer by combining chemotherapy or radiation. Two months prior to Thomas’s publication, the US National Cancer Institute, headquartered in Bethesda, Maryland, released an announcement advocating for combining chemotherapy with radiation based on clinical trial results. In “Improved Treatment,” Thomas summarized the results of those clinical trials that had led to the announcement and communicated a new way to treat invasive cervical cancers, which persists as of 2019.