Embryo Project Encyclopedia Articles

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.

William Thornton Mustard was a surgeon in Canada during the twentieth century who developed surgical techniques to treat children who had congenital heart defects. Mustard has two surgeries named after him, both of which he helped to develop. The first of these surgeries replaces damaged or paralyzed muscles in individuals who have polio, a virus that can cause paralysis. The other technique corrects a condition called the transposition of the great arteries (TGA) that is noticed at birth. Surgeons worldwide adopted that technique, leading to increased survival rates in infants afflicted with the condition. Mustard also published over 100 articles on congenital heart defects, surgical techniques, and the preparation of an artificial heart lung machine. Mustard helped perform the first blood transfusion of a newborn whose red blood cells (RBCs) had degraded, a condition called hemolytic anemia. Throughout his career, Mustard developed surgical techniques that increased the survival rates of infants and children with congenital and developmental disorders.

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.

Ignaz Philipp Semmelweis demonstrated that the use of disinfectants could reduce the occurrence of puerperal fever in patients in nineteenth century Austria. Puerperal fever is a bacterial infection that can occur in the uterine tract of women after giving birth or undergoing an abortion. Semmelweis determined that puerperal fever is contagious and argued that the unhygienic practices of physicians, like examining patients after performing autopsies, caused the spread of puerperal fever. He showed that if physicians washed their hands with a chloride solution before they attended patients, then they prevented those patients from developing puerperal fever. Despite being widely criticized during his lifetime, Semmelweis's research on the contagiousness of puerperal fever set a precedent for many scientists, and contributed to preventing the spread of puerperal fever.

Transposition of the great arteries or TGA is a potentially fatal congenital heart malformation where the pulmonary artery and the aorta are switched. The switch means that the aorta, which normally carries oxygenated blood, carries deoxygenated blood. There are two types of the malformation, d-TGA where no oxygen reaches the body and l-TGA where some oxygenated blood circulates. In the US, the Centers for Disease Control estimate that about 1,901 infants are born each year with TGA, or about one for every 2,000 births. Throughout history, physicians classified TGA as a condition that causes blue babies and hypothesized it was a fatal condition. With the development of corrective surgeries, studies on the causes of TGA, and improved prenatal diagnosis have allowed for the survival rate for those with TGA to approach almost one hundred percent.

Adib Jatene in Brazil was the first surgeon to successfully perform the arterial switch operation in 1975. The operation corrected a heart condition in infants called transposition of the great arteries (TGA). Left untreated, infants with TGA die, as their blood cannot supply oxygen to their bodies. Jatene’s operation became widely used to correct the condition. Aside from medical research, Jatene worked for years in politics and education, serving as Brazil’s minister of health and teaching thoracic surgery at the University of São Paulo.

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 arterial switch operation, also called the Jatene procedure, is an operation in which surgeons redirect the flow of blood through abnormal hearts. In 1975, Adib Jatene conducted the first successful arterial switch operation on a human infant. The arterial switch operation corrects a condition called transposition of the great arteries, abbreviated TGA, also called transposition of the great vessels, abbreviated TGV. TGA occurs when the pulmonary artery, which supplies deoxygenated blood to the lungs, and the aorta, which takes oxygenated blood to the body, are switched, or transposed. The switch between the aorta and pulmonary artery results in dangerously low levels of oxygen, a condition called cyanosis, in newborn infants, which causes them to die if a surgeon does not correct it.