For every 200,000 live births, conjoined twins are born. Conjoined twins are identical and of the same sex one hundred percent of the time and are more common in females than in males. For surgical separations the survival rate of at least one twin surviving is approximately 75%.

Maria and Teresa Tapia (born April 8, 2010) were conjoined twins born in the Dominican Republic. The twins were joined by their lower chest and abdomen and were therefore classified as omphalopagus sharing a liver, pancreas, and a small portion of their small intestine. On November 7, 2011, the twins underwent a successful separation surgery at the Children's Hospital of Richmond in Virginia.

Anastasia and Tatiana Dogaru

born August 29, 2004) are craniopagus conjoined twins. They were scheduled to begin the first of several surgeries to separate them at Rainbow Babies and Children's Medical Center in Cleveland, Ohio. However, in August 2007 the surgery was called off as too dangerous.

The twins were born in Rome, Italy to Romanian parents, Alin Dogaru, a Byzantine Catholic priest, and Claudia Dogaru, a nurse. Their mother heard about the successful separation of Egyptian-born twins who were also joined at the head and hoped her children could also be successfully separated. The Dogaru family — who also have an older daughter, Maria, and younger son Theodor — were brought to north Texas by the World Craniofacial Foundation to have Anastasia and Tatiana evaluated for possible separation.

The girls are currently developing normally for their age and speak both Romanian and English. They get around with Anastasia leading the way and Tatiana following. The top of Tatiana's head is attached to the back of Anastasia's. Anastasia, whose kidneys don't function, relies on her sister's kidneys, and Tatiana on her sister's circulatory system. The girls also share blood flow to the back of the brain and some brain matter. Doctors estimated the twins had only a 50 percent chance of surviving the surgery. There were also risks of complications, such as brain damage, but the girls also risk early death if they remain conjoined. Their parents believed separation would give them their best chance at living a normal life.

In May 2007, doctors used a catheter to insert wire coils into the veins of the two girls, successfully redirecting their blood flow. It was the first time the procedure was attempted in conjoined twins. Doctors pushed back the first of the planned separation surgeries to June 2007 while studying the complex circulatory system of the twins, but, in August of that year, decided it was too risky.

Giacomo and Giovanni Battista Tocci were two-headed conjoined twins born in Locana, Italy between 1875 and 1877 on either July or October 4.

Maria and Daria ('Masha and Dasha') Krivoshlyapova (Мария и Дарья Кривошляповы) (3 January 1950 – 17 April 2003, Moscow) were "Ischiopagus tripus" conjoined twins from Russia.

They were removed from their mother's custody at birth to be studied by Soviet physiologists. Their mother was told that her daughters had died soon after their birth.

Their mother Maria Luigia Mezzanrosa was 19 years old; she had an easy time with the birth as they were rather small. They were delivered normally, with one head appearing first, the other head and torso second, and the pelvis and legs third. The one on their right was named Giovanni Battista, and the one on their left Giacomo. They had one umbilical cord and one placenta. Their father Giovanni Tocci had a breakdown due to the appearance of his first-born sons and was put into a lunatic asylum until he recovered a month later.

Navel fetishism, belly button fetishism, or alvinophilia is a partialism in which an individual is sexually attracted to the human navel.

According to a study, it is a moderately prevalent fetish among individuals. While in 2012, it was the second most popular fetish search on Google as per their global monthly averages.

Synesthesia is found in at least 4.4% of the population, as a high estimate, which is equivalent to 1 in 23 people. This study had also concluded that one common form of synesthesia—grapheme-color synesthesia (colored letters and numbers) – is found in more than one percent of the population, and this latter prevalence of graphemes-color synesthesia has now been independently verified in a yet larger sample. Earlier estimates of the prevalence of synesthesia were based on "best-guess" estimations only ("e.g." 1 in 250,000) or had limitations in their methodologies because they required synesthetes to refer themselves for study ("e.g." 1 in 2000) and for this reason the authors of those studies had been moderate in their claims. Also, some individuals will not self-classify as synesthetes because they do not realize that their perceptions are different from those of everyone else.

The most common forms of synesthesia are those that trigger colors, and the most prevalent of all is day-color. Also relatively common is grapheme-color synesthesia. We can think of "prevalence" both in terms of how common is synesthesia (or different forms of synesthesia) within the population, or how common are different forms of synesthesia within synesthetes. So within synesthetes, forms of synesthesia that trigger color also appear to be the most common forms of synesthesia with a prevalence rate of 86% within synesthetes. In another study, music-color is also prevalent at 18–41%. Some of the rarest are reported to be auditory-tactile, mirror-touch, and lexical-gustatory.

There is research to suggest that the likelihood of having synesthesia is greater in people with autism.

Republican marriage () was a method of execution that allegedly occurred in Nantes during the Reign of Terror in Revolutionary France and "involved tying a naked man and woman together and drowning them". This was reported to have been practised during the drownings at Nantes ("noyades") that were ordered by local Jacobin representative-on-mission Jean-Baptiste Carrier between November 1793 and January 1794 in the city of Nantes. Most accounts indicate that the victims were drowned in the Loire River, although a few sources describe an alternative means of execution in which the bound couple is run through with a sword, either before, or instead of drowning.

The earliest reports of such "marriages" date from 1794, when Carrier was tried for his crimes, and they were soon cited by contemporary counter-revolutionary authors such as Louis-Marie Prudhomme and Louis Gabriel Ambroise de Bonald.

The genetic mechanism of synesthesia has long been debated. Due to the prevalence of synesthesia among the first-degree relatives of synesthetes, there is evidence that synesthesia might have a genetic basis, however the monozygotic twins case studies indicate there is an epigenetic component. Synesthesia might also be a oligogenic condition, with Locus heterogeneity, multiple forms of inheritance (including Mendelian in some cases), and continuous variation in gene expression.

In Chinese alchemy, elixir poisoning refers to the toxic effects from elixirs of immortality that contained metals and minerals such as mercury and arsenic. The official "Twenty-Four Histories" record numerous Chinese emperors, nobles, and officials who ironically died from taking elixirs in order to prolong their lifespans. The first emperor to die from elixir poisoning was likely Qin Shi Huang (d. 210 BCE) and the last was Yongzheng (d. 1735). Despite common knowledge that immortality potions could be deadly, fangshi and Daoist alchemists continued the elixir-making practice for two millennia.

Ghost sickness is a cultural belief among some traditional indigenous peoples in North America, notably the Navajo, and some Muscogee and Plains cultures, as well as among Polynesian peoples. People who are preoccupied and/or consumed by the deceased are believed to suffer from ghost sickness. Reported symptoms can include general weakness, loss of appetite, suffocation feelings, recurring nightmares, and a pervasive feeling of terror. The sickness is attributed to ghosts () or, occasionally, to witches or witchcraft. Children are thought to be especially at risk of being affected because they are not as attached to their new bodies.

One reason that poverty produces such high rates of fistula cases is the malnutrition that exists in such areas. Lack of money and access to proper nutrition, as well as vulnerability to diseases that exist in impoverished areas because of limited basic health care and disease prevention methods, cause inhabitants of these regions to experience stunted growth. Sub-Saharan Africa is one such environment where the shortest women have on average lighter babies and more difficulties during birth when compared with full-grown women. This stunted growth causes expectant mothers to have skeletons unequipped for proper birth, such as an underdeveloped pelvis. This weak and underdeveloped bone structure increases the chances that the baby will get stuck in the pelvis during birth, cutting off circulation and leading to tissue necrosis. Because of the correlation between malnutrition, stunted growth, and birthing difficulties, maternal height can at times be used as a measure for expected labor difficulties.

High levels of poverty also lead to low levels of education among impoverished women concerning maternal health. This lack of information in combination with obstacles preventing rural women to easily travel to and from hospitals lead many to arrive at the birthing process without prenatal care. This can cause a development of unplanned complications that may arise during home births, in which traditional techniques are used. These techniques often fail in the event of unplanned emergencies, leading women to go to hospital for care too late, desperately ill, and therefore vulnerable to the risks of anesthesia and surgery that must be used on them. In a study of women who had prenatal care and those who had unbooked emergency births, “the death rate in the booked-healthy group was as good as that in many developed countries, [but] the death rate in the unbooked emergencies was the same as the death rate in England in the 16th and 17th centuries.” In this study, 62 unbooked emergency women were diagnosed with obstetric fistulae out of 7,707 studied, in comparison to three diagnosed booked mothers out of 15,020 studied. In addition, studies find that education is associated with lower desired family size, greater use of contraceptives, and increased use of professional medical services. Educated families are also more likely to be able to afford health care, especially maternal healthcare.

Religious leaders within the Navajo tribe repeatedly perform ceremonies to eliminate the all-consuming thoughts of the dead.

A navel fetishist can be sexually aroused by a variety of stimuli, including key words, thoughts or specific forms of physical interaction with the navel.

Necrophilia is often assumed to be rare, but no data for its prevalence in the general population exists. Some necrophiles only fantasize about the act, without carrying it out. In 1958, Klaf and Brown commented that, although rarely described, necrophiliac fantasies may occur more often than is generally supposed.

Rosman and Resnick (1989) reviewed 122 cases of necrophilia. The sample was divided into genuine necrophiles, who had a persistent attraction to corpses, and pseudo-necrophiles, who acted out of opportunity, sadism, or transient interest. Of the total, 92% were male and 8% were female. 57% of the genuine necrophiles had occupational access to corpses, with morgue attendant, hospital orderly, and cemetery employee being the most common jobs. The researchers theorized that either of the following situations could be antecedents to necrophilia:

1. The necrophile develops poor self-esteem, perhaps due in part to a significant loss;

- (a) They are very fearful of rejection by others and they desire a sexual partner who is incapable of rejecting them; and/or

- (b) They are fearful of the dead, and transform their fear—by means of reaction formation—into a desire.

2. They develop an exciting fantasy of sex with a corpse, sometimes after exposure to a corpse.

The authors reported that, of their sample of genuine necrophiles:

- 68% were motivated by a desire for an unresisting and unrejecting partner;

- 21% by a want for reunion with a lost partner;

- 15% by sexual attraction to dead people;

- 15% by a desire for comfort or to overcome feelings of isolation; and

- 12% by a desire to remedy low self-esteem by expressing power over a corpse.

IQ data was limited, but not abnormally low. About half of the sample had a personality disorder, and 11% of true necrophiles were psychotic. Rosman and Resnick concluded that their data challenged the conventional view of necrophiles as generally psychotic, mentally deficient, or unable to obtain a consenting partner.

Islamophobia is an intense fear or hatred of, or prejudice against, the Islamic religion or Muslims, especially when seen as a geopolitical force or the source of terrorism.

The term was first used in the early 20th century and it emerged as a neologism in the 1970s, then it became increasingly salient during the 1980s and 1990s, and it reached public policy prominence with the report by the Runnymede Trust's Commission on British Muslims and Islamophobia (CBMI) entitled "Islamophobia: A Challenge for Us All" (1997). The introduction of the term was justified by the report's assessment that "anti-Muslim prejudice has grown so considerably and so rapidly in recent years that a new item in the vocabulary is needed".

The causes and characteristics of Islamophobia are still debated. Some commentators have posited an increase in Islamophobia resulting from the September 11 attacks, some from multiple terror attacks in Europe and the United States, while others have associated it with the increased presence of Muslims in the United States and in the European Union. Some people also question the validity of the term. The academics S. Sayyid and Abdoolkarim Vakil maintain that Islamophobia is a response to the emergence of a distinct Muslim public identity globally, the presence of Muslims is in itself not an indicator of the degree of Islamophobia in a society. Sayyid and Vakil maintain that there are societies where virtually no Muslims live but many institutionalized forms of Islamophobia still exist in them.

Stendhal syndrome, Stendhal's syndrome, hyperkulturemia, or Florence syndrome is a psychosomatic disorder that causes rapid heartbeat, dizziness, fainting, confusion and even hallucinations when an individual is exposed to an experience of great personal significance, particularly viewing art. It is not listed as a recognised condition in the "Diagnostic and Statistical Manual of Mental Disorders".

Catalepsy (from Greek "κατάληψις" "seizing/grasping") is a nervous condition characterized by muscular rigidity and fixity of posture regardless of external stimuli, as well as decreased sensitivity to pain.

The risk of pregnancy complications increases as the mother's age increases. Risks associated with childbearing over the age of 50 include an increased incidence of gestational diabetes, hypertension, delivery by caesarean section, miscarriage, preeclampsia, and placenta previa. In comparison to mothers between 20 and 29 years of age, mothers over 50 are at almost three times the risk of low birth weight, premature birth, and extremely premature birth; their risk of extremely low birth weight, small size for gestational age, and fetal mortality was almost double.

Though heart disease is not exclusive to the poor, there are aspects of a life of poverty that contribute to its development. This category includes coronary heart disease, stroke and heart attack. Heart disease is the leading cause of death worldwide and there are disparities of morbidity between the rich and poor. Studies from around the world link heart disease to poverty. Low neighborhood income and education were associated with higher risk factors. Poor diet, lack of exercise and limited (or no) access to a specialist were all factors related to poverty, though to contribute to heart disease.

Both low income and low education were predictors of coronary heart disease, a subset of cardiovascular disease. Of those admitted to hospital in the United States for heart failure, women and African Americans were more likely to reside in lower income neighborhoods. In the developing world, there is a 10 fold increase in cardiac events in the black and urban populations.

Poverty and disease are tied closely together, with each factor aiding the other. Many diseases that primarily affect the poor serve to also deepen poverty and worsen conditions. Poverty also significantly reduces people's capabilities making it more difficult to avoid poverty related diseases.

The majority of diseases and related mortality in poor countries is due to preventable, treatable diseases for which medicines and treatment regimes are readily available. Poverty is in many cases the single dominating factor in higher rates of prevalence of these diseases. Poor hygiene, ignorance in health-related education, non-availability of safe drinking water, inadequate nutrition and indoor pollution are factors exacerbated by poverty.

Just the big three PRDs — TB, AIDS/HIV and Malaria — account for 18% of diseases in poor countries. The disease burden of treatable childhood diseases in high-mortality, poor countries is 5.2% in terms of disability-adjusted life years but just 0.2% in the case of advanced countries.

In addition, infant mortality and maternal mortality are far more prevalent among the poor. For example, 98% of the 11,600 daily maternal and neonatal deaths occur in developing countries.

Necrophilia, also known as necrophilism, necrolagnia, necrocoitus, necrochlesis, and thanatophilia, is a sexual attraction or sexual act involving corpses. It is classified as a paraphilia by the "Diagnostic and Statistical Manual" (DSM) of the American Psychiatric Association.

Rosman and Resnick (1989) reviewed information from 34 cases of necrophilia describing the individuals' motivations for their behaviors: these individuals reported the desire to possess a non-resisting and non-rejecting partner (68%), reunions with a romantic partner (21%), sexual attraction to corpses (15%), comfort or overcoming feelings of isolation (15%), or seeking self-esteem by expressing power over a homicide victim (12%).

Facts about the conception of pregnancies in this age group can be difficult to determine, but they are nearly always due to the use of IVF with donor eggs.