Gay bowel syndrome was a medical term first used by Henry L Kazal and colleagues in 1976 to describe the various sexually transmitted perianal and rectal diseases and sexual traumas seen in Kazal's proctology practice, which had many gay patients.

After Kazal, the term was used sporadically in medical literature from the 1970s to refer to a complex of gastrointestinal symptoms affecting gay men. The term was first used in the pre-HIV era, by Kazal et al. in 1976. The term was not specific to any particular disease or infection, and was used clinically to describe proctitis and a variety of other complaints caused by a wide range of infectious organisms. Reported causes include herpes viruses, syphilis, gonorrhea, chlamydia, campylobacter, and shigellosis, as well as a variety of protozoal infections. The concept of "gay bowel syndrome" was later expanded to include various opportunistic cancers. Transmission of disease was considered to take place by two routes: anal sex, and fecal-oral route. Sometimes, difficulty in specifying the method may be a result of transmission by both methods. Following the onset of the AIDS epidemic, the reported incidence of these complaints has declined, likely as a result of safer sexual practices. Those with the ano-rectal disorder experience increased incidents of diarrhea.

Lesbophobia (sometimes lesbiphobia) comprises various forms of negativity towards lesbians as individuals, as couples, or as a social group. Based on the categories of sex, sexual orientation, lesbian identity, and gender expression, this negativity encompasses prejudice, discrimination, and abuse, in addition to attitudes and feelings ranging from disdain to hostility. As such, lesbophobia is sexism against women that intersects with homophobia and vice versa.

Biphobia is aversion toward bisexuality and toward bisexual people as a social group or as individuals. It can take the form of denial that bisexuality is a genuine sexual orientation, or of negative stereotypes about people who are bisexual (such as the beliefs that they are promiscuous or dishonest). People of any sexual orientation can experience or perpetuate biphobia, and it is a source of social discrimination against bisexual people.

Uniform fetishism is a sexual fetishism where an individual is sexually aroused by uniforms.

The World Health Organization (WHO) lists ego-dystonic sexual orientation in the ICD-10, as a disorder of sexual development and orientation. The WHO diagnosis covers when gender identity or sexual orientation is clear, yet a patient has another behavioural or psychological disorder which makes that patient want to change it. The diagnostic manual notes that a sexual orientation is not a disorder in itself. The World Health Organization (WHO) notes that any particular sexual orientation (heterosexuality, homosexuality, or bisexuality) is not a mental disorder by and of itself.

Similarly, the American Psychological Association has officially opposed the category of ego-dystonic homosexuality since 1987. In 2007, a task force of the American Psychological Association undertook a thorough review of the existing research on the efficacy of reparative therapy for. Their report noted that there was very little methodologically sound research on sexual orientation change efforts (SOCEs) and that the "results of scientifically valid research indicate that it is unlikely that individuals will be able to reduce same-sex attractions or increase other-sex sexual attractions through SOCE." In addition, the task force found that "there are no methodologically sound studies of recent SOCE that would enable the task force to make a definitive statement about whether or not recent SOCE is safe or harmful and for whom." The diagnostic category of "ego-dystonic homosexuality" was removed from the American Psychiatric Association's DSM in 1987 (with the publication of the DSM-III-R). Sexual disorders are still present in the DSM under the category of "sexual disorder not otherwise specified". One of the disorders under this category is "persistent and marked distress about one’s sexual orientation”, which can be considered similar to what WHO describes as ego-dystonic sexual orientation.

The Medical Council of India uses the WHO classification of ego-dystonic sexual orientation. The "Chinese Classification and Diagnostic Criteria of Mental Disorders" includes ego-dystonic homosexuality.

Transvestism is the practice of dressing and acting in a style or manner traditionally associated with the opposite sex. In some cultures, transvestism is practiced for religious, traditional or ceremonial reasons.

The primary symptoms of IBS are abdominal pain or discomfort in association with frequent diarrhea or constipation and a change in bowel habits. Symptoms usually are experienced as acute attacks that subside within one day, but recurrent attacks are likely. There may also be urgency for bowel movements, a feeling of incomplete evacuation (tenesmus), bloating, or abdominal distension. In some cases, the symptoms are relieved by bowel movements. People with IBS, more commonly than others, have gastroesophageal reflux, symptoms relating to the genitourinary system, chronic fatigue syndrome, fibromyalgia, headache, backache, and psychiatric symptoms such as depression and anxiety. About a third of men and women who have IBS also report sexual dysfunction typically in the form of a reduction in libido.

Ego-dystonic sexual orientation is an ego-dystonic mental disorder characterized by having a sexual orientation or an attraction that is at odds with one's idealized self-image, causing anxiety and a desire to change one's orientation or become more comfortable with one's sexual orientation. It describes not innate sexual orientation itself, but a conflict between the sexual orientation one wishes to have and the sexual orientation one actually possesses.

Transphobia is a range of negative attitudes, feelings or actions toward transgender or transsexual people, or toward transsexuality. Transphobia can be emotional disgust, fear, violence, anger or discomfort felt or expressed towards people who do not conform to society's gender expectations. It is often expressed alongside homophobic views and hence is often considered an aspect of homophobia. Transphobia is a type of prejudice and discrimination similar to racism and sexism, and transgender people of color are often subjected to all three forms of discrimination at once.

Child victims of transphobia experience harassment, school bullying, and violence in school, foster care, and social programs. Adult victims experience public ridicule, harassment including misgendering, taunts, threats of violence, robbery, and false arrest; many feel unsafe in public. A high percentage report being victims of sexual violence. Some are refused healthcare or suffer workplace discrimination, including being fired for being transgender, or feel under siege by conservative political or religious groups who oppose laws to protect them. There is even discrimination from some people within the movement for the rights of gender and sexual minorities.

Besides the increased risk of violence and other threats, the stress created by transphobia can cause negative emotional consequences which may lead to substance abuse, running away from home (in minors), and a higher rate of suicide.

In the Western world, there have been gradual changes towards the establishment of policies of non-discrimination and equal opportunity. The trend is also taking shape in developing nations. In addition, campaigns regarding the LGBT community are being spread around the world to improve acceptance; the "Stop the Stigma" campaign by the UN is one such development.

Children with persistent GID are characterized by more extreme gender dysphoria in childhood than children with desisting gender dysphoria. Some (but not all) gender diverse / gender independent / gender fluid youth will want or need to transition, which may involve social transition (changing dress, name, pronoun), and, for older youth and adolescents, medical transition (hormonal and surgical intervention). Treatment may take the form of puberty blockers such as Lupron Depot or Leuprolide Acetate, or cross-sex hormones (i.e., administering estrogen to an assigned male at birth or testosterone to an assigned female at birth), or surgery (i.e., mastectomies, salphingo-oophorectomies/hysterectomy, the creation of a neophallus in female-to-male transsexuals, orchiectomies, breast augmentation, facial feminization surgery, the creation of a neovagina in male-to-female transsexuals), with the aim of bringing one’s physical body in line with their felt gender. The ability to transition (socially and medically) are sometimes needed in the treatment of gender dysphoria.

The Endocrine Society does not recommend endocrine treatment of prepubertal children because clinical experience suggests that GID can be reliably assessed only after the first signs of puberty. It recommends treating transsexual adolescents by suppressing puberty with puberty blockers until age 16 years old, after which cross-sex hormones may be given.

The University of Washington is leading the largest study of transgender youth ever conducted. The study, known as the Transgender Youth Project, looks at 300 transgender kids between the ages of 3 and 12. Researchers hope to follow the children for 20 years.

There are many different types of rectal discharge, but the most common presentation of a discharge is passage of mucus or pus wrapped around an otherwise normal bowel movement.

Rectal discharge has many causes, and may present with other symptoms:

- Staining of undergarments

- Constant feeling of dampness around anus

- Frequent urge to open bowels, but passage of only small amounts of mucus or pus-like liquid rather than normal feces

- Rectal pain

- Rectal malodor, when the discharge is foul-smelling, e.g. associated with certain infections

- Pruritus ani

- Rectal bleeding

- Perianal erythema, swelling and tenderness

IBS can be classified as either diarrhea-predominant (IBS-D), constipation-predominant (IBS-C), or with alternating stool pattern (IBS-A) or pain-predominant. In some individuals, IBS may have an acute onset and develop after an infectious illness characterized by two or more of: fever, vomiting, diarrhea, or positive stool culture. This postinfective syndrome has consequently been termed "postinfectious IBS" (IBS-PI).

The differential diagnosis of rectal discharge is extensive, but the general etiological themes are infection and inflammation. Some lesions can cause a discharge by mechanically interfering with, or preventing the complete closure of, the anal canal. This type of lesion may not cause discharge intrinsically, but instead allow transit of liquid stool components and mucus.

- Common causes include: haemorrhoids, proctitis, anal fissure, rectal prolapse, perianal warts (anal condyloma acuminatum),

- Less common causes include: colorectal carcinoma, irritable bowel syndrome, solitary rectal ulcer syndrome, anal fistulae, villous adenoma, poor anal hygiene

- Rare causes include: sexually transmitted diseases (e.g. syphilis, rectal gonorrhea, chlamydia), anal carcinoma, AIDS, rectal foreign body, bowel obstruction, rectocele, enterocele, ulcerative colitis, bacterial colitis (e.g. syphilytic colitis), anal/perianal tuberculosis, perianal abscess (when ruptured).

Perianal Crohn's disease is associated with fistulizing, fissuring and perianal abscess formation.

After colostomy, the distal section of bowel continues to produce mucus despite fecal diversion, often resulting in mucinous discharge.

Occasionally, intestinal parasitic infection can present with discharge, for example whipworm.

FI affects virtually all aspects of peoples' lives, greatly diminishing physical and mental health, and affect personal, social and professional life. Emotional effects may include stress, fearfulness, anxiety, exhaustion, fear of public humiliation, feeling dirty, poor body-image, reduced desire for sex, anger, humiliation, depression, isolation, secrecy, frustration and embarrassment. Some people may need to be in control of life outside of FI as means of compensation. The physical symptoms such as skin soreness, pain and odor may also affect quality of life. Physical activity such as shopping or exercise is often affected. Travel may be affected, requiring careful planning. Working is also affected for most. Relationships, social activities and self-image likewise often suffer. Symptoms may worsen over time.

Gender dysphoria in children or gender identity disorder in children (GIDC) is a formal diagnosis used by psychologists and physicians to describe children who experience significant discontent (gender dysphoria) with their biological sex, assigned gender, or both.

GIDC was formalized in the third revision of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-III) in 1980 and primarily referenced gender non-conforming behaviors. GIDC remained in the DSM from 1980 to 2013, when it was replaced with the diagnosis of "gender dysphoria" in the fifth revision (DSM-5), in an effort to diminish the stigma attached to gender variance while maintaining a diagnostic route to gender affirming medical interventions such as hormone therapy and surgery.

Controversy surrounding the pathologization and treatment of cross-gender identity and behaviors, particularly in children, has been evident in the literature since the 1980s. Proponents of more widespread GIDC diagnoses argue that therapeutic intervention helps children be more comfortable in their bodies and can prevent adult gender identity disorder. Opponents say that the equivalent therapeutic interventions with gays and lesbians (titled conversion or reparative therapy) have been strongly questioned or declared unethical by the American Psychological Association, American Psychiatric Association, American Association of Social Workers and American Academy of Pediatrics. The World Professional Association for Transgender Health (WPATH) states that treatment aimed at trying to change a person's gender identity and expression to become more congruent with sex assigned at birth "is no longer considered ethical." Critics also argue that the GIDC diagnosis and associated therapeutic interventions rely on the assumption that an adult transsexual identity is undesirable, challenging this assumption along with the lack of clinical data to support outcomes and efficacy.

Gender identity disorder in children is more heavily linked with adult homosexuality than adult transsexualism. According to limited studies, the majority of children diagnosed with GID cease to desire to be the other sex by puberty, with most growing up to identify as gay or lesbian with or without therapeutic intervention.

Terms such as "functional colonic disease" (or "functional bowel disorder") refer in medicine to a group of bowel disorders which are characterised by chronic abdominal complaints without a structural or biochemical cause that could explain symptoms. Other "functional" disorders relate to other aspects of the process of digestion.

The consensus review process of meetings and publications organised by the Rome Foundation, known as the Rome process, has helped to define the functional gastrointestinal disorders. Successively, the Rome I, Rome II, Rome III and Rome IV proposed consensual classification system and terminology, as recommended by the Rome Coordinating Committee. These now include classifications appropriate for adults, children and neonates / toddlers.

The current Rome IV classification, published in 2016, is as follows:

A. Esophageal Disorders

- A1. Functional chest pain

- A2. Functional heartburn

- A3. Reflux hypersensitivity

- A4. Globus

- A5. Functional dysphagia

B. Gastroduodenal Disorders

- B1. Functional dyspepsia

- B1a. Postprandial distress syndrome (PDS)

- B1b. Epigastric pain syndrome (EPS)

- B2. Belching disorders

- B2a. Excessive supragastric belching

- B2b. Excessive gastric belching

- B3. Nausea and vomiting disorders

- B3a. Chronic nausea vomiting syndrome (CNVS}

- B3b. Cyclic vomiting syndrome (CVS)

- B3c. Cannabinoid hyperemesis syndrome (CHS)

- B4. Rumination syndrome

C. Bowel Disorders

- C1. Irritable bowel syndrome (IBS)

- IBS with predominant constipation (IBS-C)

- IBS with predominant diarrhea (IBS-D)

- IBS with mixed bowel habits (IBS-M)

- IBS unclassified (IBS-U)

- C2. Functional constipation

- C3. Functional diarrhea

- C4. Functional abdominal bloating/distension

- C5. Unspecified functional bowel disorder

- C6. Opioid-induced constipation

D. Centrally Mediated Disorders of Gastrointestinal Pain

- D1. Centrally mediated abdominal pain syndrome (CAPS)

- D2. Narcotic bowel syndrome (NBS)/ Opioid-induced GI hyperalgesia

E. Gallbladder and Sphincter of Oddi disorders

- E1. Biliary pain

- E1a. Functional gallbladder disorder

- E1b. Functional biliary sphincter of Oddi disorder

- E2. Functional pancreatic sphincter of Oddi disorder

F. Anorectal Disorders

- F1. Fecal incontinence

- F2. Functional anorectal pain

- F2a. Levator ani syndrome

- F2b. Unspecified functional anorectal pain

- F2c. Proctalgia fugax

- F3. Functional defecation disorders

- F3a. Inadequate defecatory propulsion

- F3b. Dyssynergic defecation

G. Childhood Functional GI Disorders: Neonate/Toddler

- G1. Infant regurgitation

- G2. Rumination syndrome

- G3. Cyclic vomiting syndrome (CVS)

- G4. Infant colic

- G5. Functional diarrhea

- G6. Infant dyschezia

- G7. Functional constipation

H. Childhood Functional GI Disorders: Child/Adolescent

- H1. Functional nausea and vomiting disorders

- H1a. Cyclic vomiting syndrome (CVS)

- H1b. Functional nausea and functional vomiting

- H1b1. Functional nausea

- H1b2. Functional vomiting

- H1c. Rumination syndrome

- H1d. Aerophagia

- H2. Functional abdominal pain disorders

- H2a. Functional dyspepsia

- H2a1. Postprandial distress syndrome

- H2a2. Epigastric pain syndrome

- H2b. Irritable bowel syndrome (IBS)

- H2c. Abdominal migraine

- H2d. Functional abdominal pain ‒ NOS

- H3. Functional defecation disorders

- H3a. Functional constipation

- H3b. Nonretentive fecal incontinence

Usually the patient has abdominal distention, pain and altered bowel movements. There may also be nausea and vomiting.

Functional gastrointestinal disorders are very common. Globally, irritable bowel syndrome and functional dyspepsia alone may affect 16–26% of the population.

The symptoms of short bowel syndrome can include:

- Abdominal pain

- Diarrhea and steatorrhea (oily, bulky stool, which can be malodorous)

- Fluid depletion

- Weight loss and malnutrition

- Fatigue

Persons with short bowel syndrome may have complications caused by malabsorption of vitamins and minerals, such as deficiencies in vitamins A, D, E, K, B (folic acid), and B, calcium, magnesium, iron, and zinc. These may appear as anemia, hyperkeratosis (scaling of the skin), easy bruising, muscle spasms, poor blood clotting, and bone pain.

Boot fetishism is a sexual fetish focused on boots. Boots have become the object of sexual attraction amounting to fetishism for some people and they have become a standard accessory in BDSM scenes (where leather, latex and PVC boots are favoured) and a fashion accessory in music videos. Boots are seen as perhaps the most fetishistic of all footwear and boots may be the most popular fetish clothing attire.

The initial period following the contraction of HIV is called acute HIV, primary HIV or acute retroviral syndrome. Many individuals develop an influenza-like illness or a mononucleosis-like illness 2–4 weeks post exposure while others have no significant symptoms. Symptoms occur in 40–90% of cases and most commonly include fever, large tender lymph nodes, throat inflammation, a rash, headache, and/or sores of the mouth and genitals. The rash, which occurs in 20–50% of cases, presents itself on the trunk and is maculopapular, classically. Some people also develop opportunistic infections at this stage. Gastrointestinal symptoms, such as vomiting or diarrhea may occur. Neurological symptoms of peripheral neuropathy or Guillain–Barré syndrome also occurs. The duration of the symptoms varies, but is usually one or two weeks.

Due to their nonspecific character, these symptoms are not often recognized as signs of HIV infection. Even cases that do get seen by a family doctor or a hospital are often misdiagnosed as one of the many common infectious diseases with overlapping symptoms. Thus, it is recommended that HIV be considered in people presenting an unexplained fever who may have risk factors for the infection.

The small intestine consists of the duodenum, jejunum and ileum. Inflammation of the small intestine is called enteritis, which if localised to just part is called duodenitis, jejunitis and ileitis, respectively. Peptic ulcers are also common in the duodenum.

Chronic diseases of malabsorption may affect the small intestine, including the autoimmune coeliac disease, infective Tropical sprue, and congenital or surgical short bowel syndrome. Other rarer diseases affecting the small intestine include Curling's ulcer, blind loop syndrome, Milroy disease and Whipple's disease. Tumours of the small intestine include gastrointestinal stromal tumours, lipomas, hamartomas and carcinoid syndromes.

Diseases of the small intestine may present with symptoms such as diarrhoea, malnutrition, fatigue and weight loss. Investigations pursued may include blood tests to monitor nutrition, such as iron levels, folate and calcium, endoscopy and biopsy of the duodenum, and barium swallow. Treatments may include renutrition, and antibiotics for infections.

Tenesmus is characterized by a sensation of needing to pass stool, accompanied by pain, cramping, and straining. Despite straining, little stool is passed. Tenesmus is generally associated with inflammatory diseases of the bowel, which may be caused by either infectious or noninfectious conditions. Conditions associated with tenesmus include:

- Amebiasis

- Coeliac disease

- Chronic arsenic poisoning

- Colorectal cancer

- Anal melanoma

- Cytomegalovirus (in immunocompromised patients)

- Diverticular disease

- Hemorrhoid, which are prolapsed

- Inflammatory bowel disease

- Irritable bowel syndrome

- Ischemic colitis

- Kidney stones, when a stone is lodged in the lower ureter

- Pelvic floor dysfunction

- Radiation proctitis

- Rectal gonorrhoea

- Rectal lymphogranuloma venereum

- Rectal lower gastrointestinal parasitic infection, particularly "Trichuris trichiura" (whipworm)

- Shigellosis

- Ulcerative colitis

Tenesmus (rectal) is also associated with the installation of either a reversible or non reversible stoma where rectal disease may or may not be present. Patients who experience tenesmus as a result of stoma installation can experience the symptoms of tenesmus for the duration of the stoma presence. Long term pain management may need to be considered as a result.

Diseases that affect the large intestine may affect it in whole or in part. Appendicitis is one such disease, caused by inflammation of the appendix. Generalised inflammation of the large intestine is referred to as colitis, which when caused be the bacteria "Clostridium difficile" is referred to as pseudomembranous colitis. Diverticulitis is a common cause of abdominal pain resulting from outpouchings that particularly affects the colon. Functional colonic diseases refer to disorders without a known cause, and include irritable bowel syndrome and intestinal pseudoobstruction. Constipation may result from lifestyle factors, impaction of a rigid stool in the rectum, or in neonates, Hirschprung's disease.

Diseases affecting the large intestine may cause blood to be passed with stool, may cause constipation, or may result in abdominal pain or a fever. Tests that specifically examine the function of the large intestine include barium swallows, abdominal x-rays, and colonoscopy.