Embryo Project Encyclopedia

Fetal programming, or prenatal programming, is a concept that suggests certain events occurring during critical points of pregnancy may cause permanent effects on the fetus and the infant long after birth. The concept of fetal programming stemmed from the fetal origins hypothesis, also known as Barker’s hypothesis, that David Barker proposed in 1995 at the University of Southampton in Southampton, England. The fetal origins hypothesis states that undernutrition in the womb during middle to late pregnancy causes improper fetal growth, which in turn, causes a predisposition to certain diseases in adulthood. In addition to nutritional impacts, researchers have studied the fetal programming effects of many factors, such as maternal anxiety or violence during pregnancy. Researchers proposing the concept of fetal programming established a new area of research into the developmental causes of disease, pointing towards the in utero environment and its critical role in healthy human development.

The sex of a reptile embryo partly results from the production of sex hormones during development, and one process to produce those hormones depends on the temperature of the embryo's environment. The production of sex hormones can result solely from genetics or from genetics in combination with the influence of environmental factors. In genotypic sex determination, also called genetic or chromosomal sex determination, an organism's genes determine which hormones are produced. Non-genetic sex determination occurs when the sex of an organism can be altered during a sensitive period of development due to external factors such as temperature, humidity, or social interactions. Temperature-dependent sex determination (TSD), where the temperature of the embryo's environment influences its sex development, is a widespread non-genetic process of sex determination among vertebrates, including reptiles. All crocodilians, most turtles, many fish, and some lizards exhibit TSD.

Plastination is a technique for preserving tissues, organs, and whole bodies for medical purposes and public display. Gunther von Hagens invented a form of the method in 1977 at Heidelberg University in Heidelberg, Germany after observing medical students struggle working with cadavers that quickly decomposed. Von Hagens' body models, referred to as plastinates, have since become widely used educational tools not only for those studying anatomy and medicine, but also for the general public. The technique has contributed to the fields of medicine, anatomy, and embryology by accurately preserving tissues for use in research and education.

Human pluripotent stem cells are valued for their potential to form numerous specialized cells and for their longevity. In the US, where a portion of the population is opposed to destruction of human embryos to obtain stem cells, what avenues are open to scientists for obtaining pluripotent cells that do not offend the moral sensibilities of a significant number of citizens? It is this question that the official position paper, or white paper, "Alternative Sources of Human Pluripotent Stem Cells," published in May 2005 by the President's Council on Bioethics under the chairmanship of Leon Kass, seeks to answer. Three experts external to the council, Andrew Fire from the Stanford University School of Medicine, Markus Grompe of the Oregon Health and Science University, and Janet Rossant from the Samuel Lunenfeld Research Institute in Toronto, also reviewed the white paper prior to publication.

Ricardo Hector Asch was born 26 October 1947 in Buenos Aires, Argentina, to a lawyer and French professor, Bertha, and a doctor and professor of surgery, Miguel. Asch's middle-class family lived among the largest Jewish community in Latin America, where a majority of males were professionals. After his graduation from National College No. 3 Mariano Moreno in Buenos Aires, Asch worked as a teaching assistant in human reproduction and embryology at the University of Buenos Aires School of Medicine where he received his medical degree in 1971.

Henrietta Lacks, born Loretta Pleasant, had terminal cervical cancer in 1951, and was diagnosed at The Johns Hopkins University in Baltimore, Maryland, where researchers collected and stored her cancer cells. Those cells went on to become the first immortal human cell line, which the researchers named HeLa. An immortal cell line is an atypical cluster of cells that continuously multiply on their own outside of the organism from which they came, often due to a mutation. Lacks’s cancer cells enabled scientists to study human cells outside of the human body, though that was controversial since she did not voluntarily donate her cells for such research. Science writer Rebecca Skloot chronicled Lacks’s life in her book, The Immortal Life of Henrietta Lacks, which became a movie in 2017. Lacks’s HeLa cell line has contributed to numerous biomedical research advancements and discoveries and her story has prompted legal and ethical debates over the rights that an individual has to their genetic material and tissue.

In 1942, the United States Supreme Court Case of Skinner v. Oklahoma ruled that states could not legally sterilize those inmates of prisons deemed habitual criminals. Skinner v. Oklahoma was about the case of Jack Skinner, an inmate of the Oklahoma State Penitentiary in McAlester, Oklahoma, who was subject to sterilization under the Oklahoma Habitual Criminal Sterilization Act of 1935. The case, decided on 1 June 1942, determined that state laws were unconstitutional if those laws enabled states to forcibly sterilize inmates deemed to be habitual criminals. Such laws violated the Equal Protection Clause of the Fourteenth Amendment to the US Constitution. The Skinner v. Oklahoma decision also reflected tensions in US eugenic policies when juxtaposed against similar policies of the Nazi regime in Europe, especially with regard to sterilization measures.

In 1996, the US Congress mandated that the US Environmental Protection Agency (EPA) create and regulate the Endocrine Disruptor Screening Program. The program tests industrial and agricultural chemicals for hormonal impacts in humans and in wildlife that may disrupt organisms' endocrine systems. The endocrine system regulates the release of small amounts of chemical substances called hormones to keep the body functioning normally. Some chemicals can impede the endocrine system's function by mimicking or blocking hormone reception, which can disrupt processes of development and reproduction and harm organisms. As of 2017, the Endocrine Disruptor Screening Program is the largest US program to identify and regulate chemicals that affect the normal production of sex hormones like estrogen and androgen, which can have long-term effects on development and reproduction.

A test-tube baby is the product of a successful human reproduction that results from methods beyond sexual intercourse between a man and a woman and instead utilizes medical intervention that manipulates both the egg and sperm cells for successful fertilization. The term was originally used to refer to the babies born from the earliest applications of artificial insemination and has now been expanded to refer to children born through the use of in vitro fertilization, the practice of fertilizing an embryo outside of a woman's body. The use of the term in both media and scientific publications in the twentieth century has been accompanied by discussion as well as controversy regarding the ethics of reproduction technologies such as artificial insemination and in vitro fertilization. The evolution of these terms over time mirrors the perception of our ability to manipulate the human embryo, as seen by the general public as well as the scientific community.

In the legal case In re Agent Orange Product Liability Litigation of the early 1980s, US military veterans of the Vietnam War sued the US chemical companies that had produced the herbicide Agent Orange, and those companies settled with US veterans out of court. Agent Orange contains dioxin, a chemical later shown to disrupt the hormone system of the body and to cause cancer. As veterans returned to the US from Vietnam, scientists further confirmed that exposure to Agent Orange caused a variety of cancers in veterans and developmental problems in the veterans' children. The veterans and their families held the chemical manufactures of Agent Orange liable for their injuries and the injuries to their children. The chemical companies settled the case out of court in 1984 for $180 million, to be used for medical expenses or compensation for death relating to veterans' exposure to Agent Orange. Agent Orange's use in the Vietnam War affected close to ten million people in the US, including members of the US military directly exposed to it, and their children conceived years after direct exposure.