Nosophobia is the irrational fear of contracting a disease, a type of specific phobia. Primary fears of this kind are fear of contracting HIV, pulmonary tuberculosis, venereal diseases, cancer, and heart diseases.

Some authors have suggested that the medical students' disease should accurately be referred to as "nosophobia" rather than "hypochondriasis", because the quoted studies show a very low percentage of hypochondriacal character of the condition.

The word "nosophobia" comes from the Greek νόσος "nosos" for "disease".

There can be many different reasons for why people develop genophobia. Some of the main causes are former incidents of sexual assaults or abuse. These incidents violate the victim’s trust and take away their sense of right to self-determination. Another possible cause of genophobia is the feeling of intense shame or medical reasons. Others may have the fear without any diagnosable reason.

Rape is the unconsensual and unlawful act of sexual intercourse forced by one person onto another. This can include penetration, but does not have to. Victims of rape can be female or male. “Rape is the most extreme possible invasion of a person’s physical and emotional privacy.” It is considered to be such a heinous crime because victims are attacked in a very personal manner and because physical force or deception can be utilized. Rape can be physically painful, but it can be more emotionally unbearable. Rape is often described as less of an invasion of the body and more of an invasion of “self.” Victims often have intense emotional reactions, usually in a predictable order. This is known as rape trauma syndrome.

Rape victims can experience added stress after the assault because of the way hospital staff, police personnel, friends, family, and significant others react to the situation. They can often feel lowered self-esteem and even a sense of helplessness. They long for a sense of safety and control over their lives. Rape victims can develop a fear of sex for physical and psychological reasons. During sexual assault, victims experience physical trauma such as soreness, bruising, pain, genital irritation, genital infection, severe tearing of vaginal walls, and rectal bleeding. They may also grapple with fear of the potential reoccurrence of assault. This possibility for rape can put stress on relationships as well. Some women and men can become distrusting and suspicious of others. Rape victims can become fearful of sexual intercourse because of physical pain and mental anguish.

Psychosexual conflicts, personality factors, and cultural beliefs are considered as being of etiological

significance to koro. Sexual adjustment histories of non-Chinese victims are often significant, such as premorbid sex inadequacy, sexual promiscuity, guilt over masturbation, and impotence.

When considering the biological mechanisms and evolutionary history of koro, it is important to look at it in the larger framework of mass hysteria. While the underlying mechanisms are still poorly understood, it has been suggested that the mirror neurons play a major role in mass hysteria outbreaks. Mirror neurons, which have been found in both human and non-human primates, are neurons that fire when one performs an action and when they observe another individual performing the same action. It is hypothesized that we evolved these mechanisms to learn from observation of others, as well as to facilitate imitation. However, within mirror neurons, there is some form of inhibitory process, which prevents us from blindly mimicking every action we observe others perform. New research into this area suggests that in mass hysteria outbreaks something goes amiss in this inhibitory process.