Embryo Project Encyclopedia Articles

On 29 June 1988, in Bowen v. Kendrick, the US Supreme Court ruled in a five-to-four decision that the 1981 Adolescent Family Life Act, or AFLA, was constitutional. Under AFLA, the US government could distribute federal funding for abstinence-only sexual education programs, oftentimes given to groups with religious affiliations. As a federal taxpayer, Chan Kendrick challenged the constitutionality of AFLA, claiming it violated the separation of church and state. The Supreme Court found that although AFLA funded programs that aligned with certain religious ideologies, it was constitutional because it did not encourage government involvement in religion, and it held a valid secular purpose in seeking to prevent adolescent pregnancy and premarital sexual relations. By upholding AFLA, Bowen v. Kendrick enabled the US government to continue funding abstinence-only education, which researchers have found to be ineffective.

Published in 2002, prostate cancer researcher John R. Masters authored a review article HeLa Cells 50 Years On: The Good, The Bad, and The Ugly that described the historical and contemporary context of the HeLa cell line in research in Nature Reviews Cancer. The HeLa cell line was one of the first documented immortal cell lines, isolated from cervical cancer patient Henrietta Lacks in 1951 at The Johns Hopkins Hospital in Baltimore, Maryland. An immortal cell line is a cluster of cells that continuously multiply on their own outside of the original host. Though the HeLa cell line has contributed to many biomedical research advancements such as the polio vaccine, its usage in research has been controversial for many reasons, including that Lacks was a Black woman who did not knowingly donate her cells to science. In the article “HeLa Cells 50 Years On: The Good, The Bad, and The Ugly,” Masters describes that, despite the benefits of the HeLa cell line, it has caused significant negative impacts on research due to its propensity to contaminate other cell lines, which can potentially invalidate research findings.

In “Explaining Recent Declines in Adolescent Pregnancy in the United States: The Contribution of Abstinence and Improved Contraceptive Use,” hereafter “Explaining Recent Declines,” researchers John S. Santelli, Laura Duberstein Lindberg, Lawrence B. Finer, and Susheela Singh discuss what led to the major decline in US adolescent pregnancy rates from 1995 to 2002. Working with the Guttmacher Institute, a reproductive health research organization, they found that the decline in US adolescent pregnancy rates between 1995 and 2002 was primarily due to improved contraceptive use. They published their article in 2007 after the US government had increased funding for abstinence-only education between 1998 and 2007. “Explaining Recent Declines” challenged US policies by asserting that there was minimal evidence to support abstinence-only sex education as the primary strategy to prevent adolescent pregnancy.

The Spemann-Mangold organizer, also known as the Spemann organizer, is a cluster of cells in the developing embryo of an amphibian that induces development of the central nervous system. Hilde Mangold was a PhD candidate who conducted the organizer experiment in 1921 under the direction of her graduate advisor, Hans Spemann, at the University of Freiburg in Freiburg, German. The discovery of the Spemann-Mangold organizer introduced the concept of induction in embryonic development. Now integral to the field of developmental biology, induction is the process by which the identity of certain cells influences the developmental fate of surrounding cells. Spemann received the Nobel Prize in Medicine in 1935 for his work in describing the process of induction in amphibians. The Spemann-Mangold organizer drew the attention of embryologists, and it spurred numerous experiments on the nature of induction in many types of developing embryos.

Friedrich Tiedemann studied the anatomy of humans and animals in the nineteenth century in Germany. He published on zoological subjects, on the heart of fish, the anatomy of amphibians and echinoderms, and the lymphatic and respiratory system in birds. In addition to his zoological anatomy, Tiedemann, working with the chemist Leopold Gmelin, published about how the digestive system functioned. Towards the end of his career Tiedemann published a comparative anatomy of the brains of white Europeans, black Africans, and Orangutans, in which he argued that there were no appreciable differences between the structure of the brains of blacks, women, and white European men that would suggest they were intellectually different. Tiedemann also researched the embryonic development of the brain and circulatory systems of human fetuses.

Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty times before they cannot divide any further. Researchers later found that the cause of the Hayflick Limit is the shortening of telomeres, or portions of DNA at the ends of chromosomes that slowly degrade as cells replicate. Hayflick used his research on normal embryonic cells to develop a vaccine for polio, and from HayflickÕs published directions, scientists developed vaccines for rubella, rabies, adenovirus, measles, chickenpox and shingles.

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.

On 23 April 2008, the US Government Accountability Office, or GAO, released a report titled, “Abstinence Education: Assessing the Accuracy and Effectiveness of Federally Funded Programs,” hereafter “Abstinence Education,” in which it investigated the scientific accuracy and effectiveness of abstinence-only education programs sanctioned by individual states and the US Department of Health and Human Services, or HHS. GAO is a government agency whose role is to examine the use of public funds, evaluate federal programs and activities, and provide nonpartisan support to the US Congress. In “Abstinence Education,” GAO found that as of August 2006, a variety of factors in such programs, such as inaccurate medical information, contributed to overall conclusions that abstinence-until-marriage programs were unsuccessful at reducing the rates of adolescent pregnancy. In “Abstinence Education,” GAO recommends that HHS implement procedures to better assure the accuracy of educational materials used in abstinence programs and to set standards that measure the effectiveness of those programs.

The HeLa cell line was the first immortal human cell line that George Otto Gey, Margaret Gey, and Mary Kucibek first isolated from Henrietta Lacks and developed at The Johns Hopkins Hospital in Baltimore, Maryland, in 1951. An immortal human cell line is a cluster of cells that continuously multiply on their own outside of the human from which they originated. Scientists use immortal human cell lines in their research to investigate how cells function in humans. Though the HeLa cell line has contributed to many advancements in biomedical research since the twentieth century, its usage in medical research has been controversial because Lacks did not consent to having her cells used for such purposes. As of 2020, scientists continue to use the HeLa cell line for numerous scientific advancements, such as the development of vaccines and the identification of many underlying disease mechanisms.

Jacques Loeb experimented on embryos in Europe and the United States at the end of the nineteenth and beginning of the twentieth centuries. Among the first to study embryos through experimentation, Loeb helped found the new field of experimental embryology. Notably, Loeb showed scientists how to create artificial parthenogenesis, thus refuting the idea that spermatozoa alone were necessary to develop eggs into embryos and confirming the idea that the chemical constitution of embryos environment affected their development. Furthermore, Loeb' s work showed that scientists could manipulate materials in a laboratory to create, as he called the process, the beginning stages of life.