A number of medical reports of phimosis incidence have been published over the years. They vary widely because of the difficulties of distinguishing physiological phimosis (developmental nonretractility) from pathological phimosis, definitional differences, ascertainment problems, and the multiple additional influences on post-neonatal circumcision rates in cultures where most newborn males are circumcised. A commonly cited incidence statistic for pathological phimosis is 1% of uncircumcised males. When phimosis is simply equated with nonretractility of the foreskin after age 3 years, considerably higher incidence rates have been reported.

Others have described incidences in adolescents and adults as high as 50%, though it is likely that many cases of physiological phimosis or partial nonretractility were included.

The most acute complication is paraphimosis. In this condition, the glans is swollen and painful, and the foreskin is immobilized by the swelling in a partially retracted position. The proximal penis is flaccid. Some studies found phimosis to be a risk factor for urinary retention and carcinoma of the penis.

Frenulum breve may be complicated by tearing of the frenulum during sexual or other activity and is a cause of dyspareunia. It may lead to erroneous labelling of the sufferer as having psychosexual problems. The torn frenulum may result in healing with scar tissue that is less flexible after the incident causing further difficulties. However, this tearing can also solve the problem, healing such that the frenulum is longer and therefore no longer problematic. The diagnosis of frenulum breve is almost always confused with that of phimosis and a generally tight foreskin, since the symptom is difficulty retracting the foreskin. Most men with phimosis also have frenulum breve to a certain extent.

Frenulum breve, or short frenulum, is a condition in which the frenulum of the penis, which is an elastic band of tissue under the glans penis that connects to the foreskin and helps contract it over the glans, is too short and thus restricts the movement of the foreskin. The frenulum should normally be sufficiently long and supple to allow for the full retraction of the foreskin so that it lies smoothly back on the shaft of the erect penis.

The penile frenulum is comparable to the tongue's frenulum between the tongue's lower surface and the lower jaw, or the frenulum between the upper lip and the outside of the upper gum.

The primary contributing factor to labial fusion is low estrogen levels. A vulva with low estrogen exposure, such as that of a preadolescent, has delicate epithelial lining and is therefore vulnerable to irritation. Conditions causing irritation, such as infection, inflammation and trauma, cause the edges of the labia minora to fuse together. The fusion typically begins at the posterior frenulum of the labia minora and continues anteriorly.

Most labial adhesions resolve spontaneously before puberty as estrogen levels increase and the vaginal epithelium becomes cornified.

Labial fusion is not uncommon in infants and young girls. It is most common in infants between the ages of 13 and 23 months, and has an incidence of 3.3% in this age group. It is estimated that labial fusion occurs in 1.8% of all prepubertal girls. It is rare in adult women, particularly in reproductive age, but is occasionally found in postpartum and postmenopausal women.

Opinion varies regarding how frequently ankyloglossia truly causes problems. Some professionals believe it is rarely symptomatic, whereas others believe it is associated with a variety of problems. The disagreement among professionals was documented in a study by Messner and Lalakea (2000). The authors sent a survey to a total of 1598 otolaryngologists, pediatricians, speech-language pathologists and lactation consultants with questions to ascertain their beliefs on ankyloglossia. 797 of the surveys were fully completed and used in the study. It was found that 69% of lactation consultants, but only a minority of pediatricians answered that ankyloglossia is frequently associated with feeding difficulties; 60% of otolaryngologists and 50% of speech pathologists answered that ankyloglossia is sometimes associated with speech difficulties compared to only 23% of pediatricians; 67% of otolaryngologists compared with 21% of pediatricians answered that ankyloglossia is sometimes associated with social and mechanical difficulties. Limitations of this study include a reduced sample size due to unreturned or incomplete surveys.

Ankyloglossia can affect eating, speech, and oral hygiene as well as have mechanical/social effects. Ankyloglossia can also prevent the tongue from contacting the anterior palate. This can then promote an infantile swallow and hamper the progression to an adult-like swallow which can result in an open bite deformity. It can also result in mandibular prognathism; this happens when the tongue contacts the anterior portion of the mandible with exaggerated anterior thrusts.

Rectovestibular fistula is the most common defect of the rectum and anal canal in females.

Because the cause of facial clefts still is unclear, it is difficult to say what may prevent children being born with facial clefts. It seems that folic acid contributes to lowering the risk of a child being born with a facial cleft.

A rectovestibular fistula, also referred to simply as a vestibular fistula, is an anorectal congenital disorder where an abnormal connection (fistula) exists between the rectum and the vulval vestibule of the female genitalia.

If the fistula occurs within the hymen, it is known as a rectovaginal fistula, a much rarer condition.

A facial cleft is an opening or gap in the face, or a malformation of a part of the face. Facial clefts is a collective term for all sorts of clefts. All structures like bone, soft tissue, skin etc. can be affected. Facial clefts are extremely rare congenital anomalies. There are many variations of a type of clefting and classifications are needed to describe and classify all types of clefting. Facial clefts hardly ever occur isolated; most of the time there is an overlap of adjacent facial clefts.

OAFNS is a combination of FND and oculo-auriculo-vertebral spectrum (OAVS).

The diagnosis of OAVS is based on the following facial characteristics: microtia (underdeveloped external ear), preauricular tags, facial asymmetry, mandibular hypoplasia and epibulbar lipodermoids (benign tumor of the eye which consists of adipose and fibrous tissue).

There still remains discussion about the classification and the minimal amount of characteristics. When someone presents with FND and the characteristics of OAVS, the diagnosis OAFNS may be made.

As the incidence of OAFNS is unknown, there are probably a lot of children with mild phenotypes that aren’t being diagnosed as being OAFNS.

The cause of OAFNS is unknown, but there are some theories about the genesis. Autosomal recessive inheritance is suggested because of a case with two affected siblings and a case with consanguineous parents. However, another study shows that it is more plausible that OAFNS is sporadic.

It is known that maternal diabetes plays a role in developing malformations of craniofacial structures and in OAVS. Therefore, it is suggested as a cause of OAFNS. Folate deficiency is also suggested as possible mechanism.

Low-dose CT protocols should be considered in diagnosing children with OAFNS.

There is still some discussion on whether FND is sporadic or genetic. The majority of FND cases are sporadic. Yet, some studies describe families with multiple members with FND. Gene mutations are likely to play an important role in the cause. Unfortunately, the genetic cause for most types of FND remains undetermined.

A diastema (plural diastemata) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. Diastemata are common for children and can exist in adult teeth as well. Diastemata are primarily caused by imbalance in the relationship between the jaw and the size of teeth. If the labial frenulum (lip tissue) pulls, it can also push the teeth apart and cause a diastema between the center of the two front teeth.

Urbach–Wiethe disease is very rare; there are fewer than 300 reported cases in medical literature. Although Urbach–Wiethe disease can be found worldwide, almost a quarter of reported diagnoses are in South Africa. Many of these are in patients of Dutch, German, and Khoisan ancestry. This high frequency is thought to be due to the founder effect. Due to its recessive genetic cause and the ability to be a carrier of the disease without symptoms, Urbach–Wiethe disease often runs in families. In some regions of South Africa, up to one in 12 individuals may be carriers of the disease. Most of the case studies involving Urbach–Wiethe disease patients involve only one to three cases and these cases are often in the same family. Due to its low incidence, it is difficult to find a large enough number of cases to adequately study the disease.

Orofaciodigital syndrome 1 (OFD1), also called Papillon-League and Psaume syndrome, is an X-linked congenital disorder characterized by malformations of the face, oral cavity, and digits with polycystic kidney disease and variable involvement of the central nervous system.

Urbach–Wiethe disease is typically not a life-threatening condition. The life expectancy of these patients is normal as long as the potential side effects of thickening mucosa, such as respiratory obstruction, are properly addressed. Although this may require a tracheostomy or carbon dioxide laser surgery, such steps can help ensure that individuals with Urbach–Wiethe disease are able to live a full life. Oral dimethyl sulfoxide (DMSO) has been shown to reduce skin lesions, helping to minimize discomfort for these individuals.

Recent findings in genetic research have suggested that a large number of genetic disorders, both genetic syndromes and genetic diseases, that were not previously identified in the medical literature as related, may be, in fact, highly related in the genotypical root cause of these widely varying, phenotypically-observed disorders. Orofaciodigital syndrome has been found to be a ciliopathy. Other known ciliopathies include primary ciliary dyskinesia, Bardet-Biedl syndrome, polycystic kidney disease and polycystic liver disease, nephronophthisis, Alstrom syndrome, Meckel-Gruber syndrome and some forms of retinal degeneration.

In humans, the term is most commonly applied to an open space between the upper incisors (front teeth). It happens when there is an unequal relationship between the size of the teeth and the jaw.

Diastema is sometimes caused or exacerbated by the action of a labial frenulum (the tissue connecting the lip to the gum) causing high mucosal attachment and less attached keratinized tissue which is more prone to recession or by tongue thrusting, which can push the teeth apart.

In "The Canterbury Tales", Geoffrey Chaucer wrote of the "gap-toothed wife of Bath". As early as this time period, the gap between the front teeth, especially in women, was associated with lustful characteristics. Thus, the implication in describing "the gap-toothed wife of Bath" is that she is a middle-aged woman with insatiable lust. This has no scientific basis, but it has been a common premise in folklore since the Middle Ages.

In Ghana, Namibia and Nigeria, diastemata are regarded as being attractive and a sign of fertility, and some people have even had them created through cosmetic dentistry.

In France, they are called "dents du bonheur" ("lucky teeth"). This expression originated in Napoleon's time: when the Napoleonic army recruited, it was imperative that soldiers had incisors in perfect condition because they had to open the paper cartridges (containing powder and ball) with their teeth when loading their muskets. All those who had teeth apart were then classified as unfit to fight. Some men broke their own teeth to avoid going to war. Les Blank's "Gap-Toothed Women" is a documentary film about diastematic women.

Some well-known people noted for having diastema include country music singer Charley Pride, models Jessica Hart, Lindsey Wixson, Lauren Hutton, Georgia May Jagger and Lara Stone, American television news reporter and anchor Michelle Charlesworth, American football player Michael Strahan, actresses Vanessa Paradis, Léa Seydoux, Amira Casar, Eve Myles, Cécile de France, Béatrice Dalle, Jorja Fox, Anna Paquin and Uzo Aduba, singer/guitarist Ray Davies of The Kinks, musician Elvis Costello, actors Ernest Borgnine, Terry-Thomas, and Jamaica's Keith 'Shebada' Ramsay, singers Madonna, Melanie Martinez, Becky G, and Laura Pausini, singer Edmund Sylvers, singer-songwriters Elton John, Mac DeMarco and Seal, rock musician Flea, rapper 50 Cent, former late night TV show host David Letterman, antiques expert and TV personality Tim Wonnacott, guitarist Steve Howe, comedian Paul F. Tompkins, professional wrestler and former TNA World Heavyweight Champion Bobby Roode, Major League Baseball player Jimmy Rollins, singer Bobby Brown and his daughter Bobbi Kristina Brown, former U.S. Secretary of State Condoleezza Rice., and according to released photos the daughters of the last Tsar the Grand Duchess Olga Nikolaevna of Russia, Grand Duchess Tatiana Nikolaevna of Russia, Grand Duchess Maria Nikolaevna of Russia, Grand Duchess Anastasia Nikolaevna of Russia and their brother the Tsarevich Alexei Nikolaevich of Russia.

Speech delay, also known as alalia, refers to a delay in the development or use of the mechanisms that produce speech. Speech, as distinct from language, refers to the actual process of making sounds, using such organs and structures as the lungs, vocal cords, mouth, tongue, teeth, etc. Language delay refers to a delay in the development or use of the knowledge of language.

Because language and speech are two independent stages, they may be individually delayed. For example, a child may be delayed in speech (i.e., unable to produce intelligible speech sounds), but not delayed in language. In this case, the child would be attempting to produce an age appropriate amount of language, but that language would be difficult or impossible to understand. Conversely, since a child with a language delay typically has not yet had the opportunity to produce speech sounds, it is likely to have a delay in speech as well.

At times, speech delay and impairment is caused by a physical disruption in the mouth such as a deformed frenulum, lips, or palate. If the motion or ability to form words and appropriate sounds is disrupted, the child may be slow to pick up words and lack the ability to shape their mouth and tongue in the formation of words.

Other more serious concerns are those that can be caused by oral-motor issues. Oral-motor dysfunction refers to a lack or delay in the area of the brain that speech is formed and created and communicated to the mouth and tongue. While speech may be the only concern, this disorder can be highlighted with feeding issues as well.

Children that are having speech delay disorders could have the following characteristics (Shriberg 1982):

- Speech mechanism in which speech is associated with hearing, motor speech and craniofacial malfunction

- Cognitive-linguistic aspects in which the impairment is associated with the child's intellectual, receptive, expressive and linguistic ability.

- Psychosocial issues in which the impairment is associated with caregiver, school environment, and the child's self behaviors such as aggression and maturity

The many other causes of speech delay include bilingual children with phonological disorders autism spectrum disorders, childhood apraxia, Auditory processing disorder, prematurity, cognitive impairment and hearing loss. Broomfield and Dodd's (2004a) found out after survey that 6.4% of children who are perfectly normal showed speech difficulty while they lacked these disorders will often show early signs and are at times identified as "at risk" when the speech delay is diagnosed.

The prevalence of IBS varies by country and by age range examined. The bar graph at right shows the percentage of the population reporting symptoms of IBS in studies from various geographic regions (see table below for references). The following table contains a list of studies performed in different countries that measured the prevalence of IBS and IBS-like symptoms:

While the causes of IBS are still unknown, it is believed that the entire gut–brain axis is affected.

The risk of developing IBS increases six-fold after acute gastrointestinal infection. Postinfection, further risk factors are young age, prolonged fever, anxiety, and depression. Psychological factors, such as depression or anxiety, have not been shown to cause or influence the onset of IBS, but may play a role in the persistence and perceived severity of symptoms. Nevertheless, they may worsen IBS symptoms and the patient quality of life. Antibiotic use also appears to increase the risk of developing IBS. Research has found that genetic defects in innate immunity and epithelial homeostasis increase the risk of developing both post-infectious as well as other forms of IBS.

Neurotoxic shellfish poisoning (NSP) is caused by the consumption of shellfish contaminated by breve-toxins or brevetoxin analogs.

Symptoms in humans include vomiting and nausea and a variety of neurological symptoms such as slurred speech. No fatalities have been reported but there are a number of cases which led to hospitalization.