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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.
In 1976, midwife Ina May Gaskin published Spiritual Midwifery, with other editions published in 1980, 1990, and 2003. Spiritual Midwifery is a book about pregnancy, birth, and postpartum, or the time period after birth. During the 1970s, it was common for women to receive an epidural, a medication that reduces pain during labor, and for physicians to monitor a fetus’s heartbeat while separating women from their infants after birth. However, according to Gaskin, some women wanted to give birth outside of the hospital without medical interventions. Spiritual Midwifery is a collection of birth stories from women, information about pregnancy and giving birth, and instructions to midwives on how to care for women during childbirth and the period that followed. In Spiritual Midwifery, Gaskin introduced homebirth and midwifery to a broader audience, which helped repopularize midwifery in the US.
Hans Peter Dietz and Judy Simpson published, “Levator Trauma is Associated with Pelvic Organ Prolapse,” in the journal BJOG: An International Journal of Obstetrics and Gynecology in 2008. In their article, Dietz and Simpson estimated the risk of pelvic organ prolapse in women who attained injuries to the pelvic levator muscles. The levator muscles, also known as the levator ani, are a major muscle group that comprise the pelvic floor. Along with other muscles, the pelvic floor supports organs in a woman’s pelvis, such as the bladder, uterus, and rectum. Vaginal childbirth can cause a weakening of the pelvic muscles. That can lead to pelvic organ prolapse, which results in the descent of the pelvic organs towards a woman’s vaginal opening. In, “Levator Trauma is Associated with Pelvic Organ Prolapse,” Dietz and Simpson found that women were more likely to have pelvic organ prolapse if they had levator trauma, and called for further research to understand the relationship between levator ani trauma and pelvic organ prolapse.
Screening for Breast Cancer with Mammography is a Cochrane systematic review originally published by Peter Gøtzsche and Karsten Jørgensen in 2001 and updated multiple times by 2013. In the 2013 article, the authors discuss the reliability of the results from different clinical trials involving mammography and provide their conclusions about whether mammography screening is useful in preventing deaths from breast cancer. Mammography is an X-ray technique used to detect abnormalities in breast tissue, such as breast cancer, which affects about twelve percent of women in the world and has a significant risk of mortality. The authors concluded that mammography screenings reduced breast cancer mortality, but resulted in problems such as overdiagnosis and overtreatment of screened women. The article Screening for Breast Cancer with Mammography contributed to the then ongoing controversy about the usefulness of mammography and provided accessible information about mammograms in seven languages.
Walter Jakob Gehring discovered the homeobox, a DNA segment found in a specific cluster of genes that determine the body plan of animals, plants, and fungi. Gehring identified the homeobox in 1983, with the help of colleagues while isolating the Antennapedia (Antp) gene in fruit flies (Drosophila) at the University of Basel in Basel, Switzerland. Hox genes, a family of genes that have the homeobox, determine the head-to-tail (anterior-posterior) body axis of both vertebrates and invertebrates. Gehring also identified the homeobox-containing Pax-6 gene as the master control gene in eye development of Drosophila, the same gene that, when mutated or absent in humans, leads to aniridia, or lack of the iris, in humans. Gehring's work with the homeobox suggested to biologists that widely different species share a similar and evolutionarily conserved genetic pathway that controls the development of overall body plans, from fruit flies to humans.
The Silent Scream is an anti-abortion film released in 1984 by American Portrait Films, then based in Brunswick, Ohio. The film was created and narrated by Bernard Nathanson, an obstetrician and gynecologist from New York, and it was produced by Crusade for Life, an evangelical anti-abortion organization. In the video, Nathanson narrates ultrasound footage of an abortion of a twelve-week-old fetus, claiming that the fetus opened its mouth in what Nathanson calls a silent scream during the procedure. As a result of Nathanson's anti-abortion stance in the film, The Silent Scream contributed to the abortion debate in the 1980s.
Edwin Stephen Goodrich studied the structures of animals in England during the nineteenth and twentieth centuries. Goodrich studied how animals develop to identify their parts and to establish the evolutionary relationships between different species. Goodrich established that body structures can shift their positions relative to an organism's body during evolution, and he hypothesized that body structures can share ancestry (homology) between organisms of different species, even without identical body placement. Goodrich claimed that any given characteristic of an organism results from both genetic and external sources.
Telomeres are sequences of DNA on the ends of chromosomes that protect chromosomes from sticking to each other or tangling, which could cause irregularities in normal DNA functions. As cells replicate, telomeres shorten at the end of chromosomes, which correlates to senescence or cellular aging. Integral to this process is telomerase, which is an enzyme that repairs telomeres and is present in various cells in the human body, especially during human growth and development. Telomeres and telomerase are required for normal human embryonic development because they protect DNA as it completes multiple rounds of replication.
In 2003, Carmina Gisbert and her research team produced a tobacco plant that could remove lead from soil. To do so, they inserted a gene from wheat plants that produces phytochelatin synthase into a shrub tobacco plant (Nicotiana glauca) to increase N. glauca's absorption and tolerance of toxic metals, particularly lead and cadmium. Gisbert and her team aimed to genetically modify a plant so that it could be used for phytoremediation- using plants to remove toxic substances from the soil. Scientists have identified phytoremediation as an effective and efficient process to improve human health and reproductive health in contaminated areas. Metals like mercury and lead can cause birth defects during human development like cognitive impairment, cerebral palsy, deafness, tremors, and blindness.
In the early twentieth century, Paul Kammerer conducted a series of experiments to demonstrate that organisms could transmit characteristics acquired in their lifetimes to their offspring. In his 1809 publication, zoologist Jean-Baptiste Lamarck had hypothesized that living beings can inherit features their parents or ancestors acquired throughout life. By breeding salamanders, as well as frogs and other organisms, Kammerer tested Lamarck's hypothesis in an attempt to provide evidence for Lamarck's theory of the inheritance of acquired characteristics. In particular, Kammerer argued that the inheritance of acquired characteristics caused species to evolve, and he claimed that his results provided an explanation for evolutionary processes through developmental phenomena.