The Hayflick Limit is a concept that helps to explain the mechanisms behind cellular aging. The concept states that a normal human cell can only replicate and divide forty to sixty times before it cannot divide anymore, ...

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 ...

In 1616 in Padua, Italy, Fortunio Liceti, a professor of natural philosophy and medicine, wrote and published the first edition of De Monstruorum Causis, Natura et Differentiis (On the Reasons, Nature, and Differences of ...

In the mid-1960s, psychologist John Money encouraged the gender reassignment of David Reimer, who was born a biological male but suffered irreparable damage to his penis as an infant. Born in 1965 as Bruce Reimer, his penis ...

Fetus in fetu is a rare variety of parasitic twins , where the developmentally abnormal parasitic twin is completely encapsulated within the torso of the otherwise normally developed host twin. In the late eighteenth ...

In 1907, researchers Bernhardt Kronig and Carl Gauss combined the drugs morphine and scopolamine to induce twilight sleep in women during childbirth. Physicians in the early twentieth century in Germany used twilight sleep, ...

Between 1925 and 1961, a Roman Catholic order of nuns called the Bon Secours Sisters operated the Bon Secours Mother and Baby Home, or the Home, an institution where unmarried pregnant women gave birth in Tuam, Ireland. ...

In 2010, the Catholic Church excommunicated Margaret McBride, a nun and ethics board member at St. Joseph’s Hospital and Medical Center in Phoenix, Arizona. McBride was excommunicated latae sententiae, or automatically, ...

In 1956, Gunther Stent, a scientist at the University of California Berkeley in Berkeley, California, coined the terms conservative, semi-conservative, and dispersive to categorize the prevailing theories about how DNA ...

A vaginal speculum is a medical device that allows physicians and health providers to better view a woman’s cervix and vagina during pelvic exams. Most specula are made of metal and plastic, and physicians insert a portion ...