The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders lists the following sexual dysfunctions:

- Hypoactive sexual desire disorder (see also asexuality, which is not classified as a disorder)

- Sexual aversion disorder (avoidance of or lack of desire for sexual intercourse)

- Female sexual arousal disorder (failure of normal lubricating arousal response)

- Male erectile disorder

- Female orgasmic disorder (see Anorgasmia)

- Male orgasmic disorder (see Anorgasmia)

- Premature ejaculation

- Dyspareunia

- Vaginismus

Additional DSM sexual disorders that are not sexual dysfunctions include:

- Paraphilias

- PTSD due to genital mutilation or childhood sexual abuse

Delayed ejaculation can be "mild" (men who still experience orgasm during intercourse, but only under certain conditions), "moderate" (cannot ejaculate during intercourse, but can during fellatio or manual stimulation), "severe" (can ejaculate only when alone), or "most severe" (cannot ejaculate at all). All forms may result in a sense of sexual frustration.

Sexual dysfunction disorders may be classified into four categories: sexual desire disorders, arousal disorders, orgasm disorders and pain disorders.

Delayed ejaculation, also called "retarded ejaculation" or "inhibited ejaculation," is a man's inability for or persistent difficulty in achieving orgasm, despite typical sexual desire and sexual stimulation. Generally, a man can reach orgasm within a few minutes of active thrusting during sexual intercourse, whereas a man with delayed ejaculation either does not have orgasms at all or cannot have an orgasm until after prolonged intercourse which might last for 30–45 minutes or more. In most cases, delayed ejaculation presents the condition in which the man can climax and ejaculate only during masturbation, but not during sexual intercourse. It is the least common of the male sexual dysfunctions, and can result as a side effect of some medications. In one survey, 8% of men reported being unable to achieve orgasm over a 2-month period or longer in the previous year.

Anorgasmia, or Coughlan's syndrome, is a type of sexual dysfunction in which a person cannot achieve orgasm despite adequate stimulation. In males, it is most closely associated with delayed ejaculation. Anorgasmia can often cause sexual frustration. Anorgasmia is far more common in females (4.7 percent) than in males and is especially rare in younger men. The problem is greater in women who are post-menopause.

The condition is sometimes classified as a psychiatric disorder. However, it can also be caused by medical problems such as diabetic neuropathy, multiple sclerosis, genital mutilation, complications from genital surgery, pelvic trauma (such as from a straddle injury caused by falling on the bars of a climbing frame, bicycle or gymnastics beam), hormonal imbalances, total hysterectomy, spinal cord injury, cauda equina syndrome, uterine embolisation, childbirth trauma (vaginal tearing through the use of forceps or suction or a large or unclosed episiotomy), vulvodynia and cardiovascular disease.

A common cause of situational anorgasmia, in both men and women, is the use of anti-depressants, particularly selective serotonin reuptake inhibitors (SSRIs). Though reporting of anorgasmia as a side effect of SSRIs is not precise, studies have found that 17–41% of users of such medications are affected by some form of sexual dysfunction.

Another cause of anorgasmia is opiate addiction, particularly to heroin.

About 15% of women report difficulties with orgasm, and as many as 10% of women in the United States have never climaxed. Only 29% of women always have orgasms with their partner.

Premature ejaculation (PE) occurs when a man experiences orgasm and expels semen soon after sexual activity and with minimal penile stimulation. It has also been called "early ejaculation," "rapid ejaculation," "rapid climax," "premature climax," and (historically) "ejaculatio praecox." There is no uniform cut-off defining "premature", but a consensus of experts at the International Society for Sexual Medicine endorsed a definition including "ejaculation which always or nearly always occurs prior to or within about one minute". The International Classification of Diseases (ICD-10) applies a cut-off of 15 seconds from the beginning of sexual intercourse. Hong argued that rapid ejaculation is an evolutionary adaptation.

Although men with premature ejaculation describe feeling that they have less control over ejaculating, it is not clear if that is true, and many or most average men also report that they wish they could last longer. Men's typical ejaculatory latency is approximately 4–8 minutes. The opposite condition is delayed ejaculation.

Men with PE often report emotional and relationship distress, and some avoid pursuing sexual relationships because of PE-related embarrassment. Compared with men, women consider PE less of a problem, but several studies show that the condition also causes female partners distress.

HSDD was listed under the Sexual and Gender Identity Disorders of the DSM-IV. In the DSM-5, it was split into male hypoactive sexual desire disorder and female sexual interest/arousal disorder. It was first included in the DSM-III under the name inhibited sexual desire disorder, but the name was changed in the DSM-III-R. Other terms used to describe the phenomenon include sexual aversion and sexual apathy. More informal or colloquial terms are "frigidity" and "frigidness".

In the DSM-5, male hypoactive sexual desire disorder is characterized by "persistently or recurrently deficient (or absent) sexual/erotic thoughts or fantasies and desire for sexual activity", as judged by a clinician with consideration for the patient's age and cultural context. Female sexual interest/arousal disorder is defined as a "lack of, or significantly reduced, sexual interest/arousal", manifesting as at least three of the following symptoms: no or little interest in sexual activity, no or few sexual thoughts, no or few attempts to initiate sexual activity or respond to partner's initiation, no or little sexual pleasure/excitement in 75%-100% of sexual experiences, no or little sexual interest in internal or external erotic stimuli, and no or few genital/nongenital sensations in 75%-100% of sexual experiences.

For both diagnoses, symptoms must persist for at least six months, cause clinically significant distress, and not be better explained by another condition. Simply having lower desire than one's partner is not sufficient for a diagnosis. Self-identification of a lifelong lack of sexual desire as asexuality precludes diagnosis.

The 1948 Kinsey Report suggested that three-quarters of men ejaculate within two minutes of penetration in over half of their sexual encounters.

Current evidence supports an average intravaginal ejaculation latency time (IELT) of six and a half minutes in 18- to 30-year-olds. If the disorder is defined as an IELT percentile below 2.5, then premature ejaculation could be suggested by an IELT of less than about two minutes. Nevertheless, it is possible that men with abnormally low IELTs could be satisfied with their performance and do not report a lack of control. Likewise, those with higher IELTs may consider themselves premature ejaculators, suffer from detrimental side effects normally associated with premature ejaculation, and even benefit from treatment.

Physical arousal caused by this syndrome can be very intense and persist for extended periods, days or weeks at a time. Orgasm can sometimes provide temporary relief, but within hours the symptoms return. The return of symptoms, with the exception of known triggers, is sudden and unpredictable. Failure or refusal to relieve the symptoms often results in waves of spontaneous orgasms in women and ejaculation in men. The symptoms can be debilitating, preventing concentration on mundane tasks. Some situations, such as riding in an automobile or train, vibrations from mobile phones, and even going to the toilet can aggravate the syndrome unbearably causing the discomfort to verge on pain. It is not uncommon for sufferers to lose some or all sense of pleasure over the course of time as release becomes associated with relief from pain rather than the experience of pleasure. Some sufferers have said that they shun sexual relations, which they may find to be a painful experience. The condition may last for many years and can be so severe that it has been known to lead to depression and even suicide.

A Dutch study has connected PGAD with restless legs syndrome.

It can depend on one or more of several causes, including:

- Sexual inhibition

- Pharmacological inhibition. They include mostly antidepressant and antipsychotic medication, and the patients experiencing that tend to quit them

- Autonomic nervous system

- Prostatectomy - surgical removal of the prostate.

- Ejaculatory duct obstruction

- Spinal cord injury causes sexual dysfunction including anejaculation. The rate of being able to ejaculate varies with the type of lesion, as detailed in the table at right.

- old age

Anejaculation, especially the "orgasmic" variant, is usually indistinguishable from retrograde ejaculation. However, a negative urinalysis measuring no abnormal presence of spermatozoa in the urine will eliminate a retrograde ejaculation diagnosis.

Thus, if the affected man has the sensations and involuntary muscle-contractions of an orgasm but no or very low-volume semen, ejaculatory duct obstruction is another possible underlying pathology of anejaculation.

The person experiences sneezing as a result of sexual thoughts, arousal, intercourse, or orgasm. Sneezing occurs independent of external nasal stimuli or allergens, and may occur at any point during a sexual experience. Both men and women are affected by the phenomenon.

Anejaculation is the pathological inability to ejaculate in males, with ("orgasmic") or without ("anorgasmic") orgasm.

Phallophobia in its narrower sense is a fear of the erect penis and in a broader sense an excessive aversion to masculinity.

There is not enough known about persistent genital arousal disorder to definitively pinpoint a cause. Medical professionals think it is caused by an irregularity in sensory nerves, and note that the disorder has a tendency to strike post-menopausal women, or those who have undergone hormonal treatment.

Normally, a human being is able to feel pleasure from an orgasm. Upon reaching a climax, chemicals are released in the brain and motor signals are activated that will cause quick cycles of muscle contraction in the corresponding areas of both males and females. Sometimes, these signals can cause other involuntary muscle contractions such as body movements and vocalization. Finally, during orgasm, upward neural signals go to the cerebral cortex and feelings of intense pleasure are experienced. People who have this disorder are aware of reaching an orgasm, as they can feel the physical effects of it, but they experience very limited or no sort of pleasure.

Although spinal cord injury (SCI) often causes sexual dysfunction, many people with SCI are able to have satisfying sex lives. Physical limitations acquired from SCI affect sexual function and sexuality in broader areas, which in turn has important effects on quality of life. Damage to the spinal cord impairs its ability to transmit messages between the brain and parts of the body below the level of the lesion. This results in lost or reduced sensation and muscle motion, and affects orgasm, erection, ejaculation, and vaginal lubrication. More indirect causes of sexual dysfunction include pain, weakness, and side effects of medications. Psycho-social causes include depression and altered self-image. Many people with SCI have satisfying sex lives, and many experience sexual arousal and orgasm. People with SCI employ a variety of adaptations to help carry on their sex lives healthily, by focusing on different areas of the body and types of sexual acts. Neural plasticity may account for increases in sensitivity in parts of the body that have not lost sensation, so people often find newly sensitive erotic areas of the skin in erogenous zones or near borders between areas of preserved and lost sensation.

Drugs, devices, surgery, and other interventions exist to help men achieve erection and ejaculation. Although male fertility is reduced, many men with SCI can still father children, particularly with medical interventions. Women's fertility is not usually affected, although precautions must be taken for safe pregnancy and delivery. People with SCI need to take measures during sexual activity to deal with SCI effects such as weakness and movement limitations, and to avoid injuries such as skin damage in areas of reduced sensation. Education and counseling about sexuality is an important part of SCI rehabilitation but is often missing or insufficient. Rehabilitation for children and adolescents aims to promote healthy development of sexuality and includes education for them and their families. Culturally inherited biases and stereotypes negatively affect people with SCI, particularly when held by professional caregivers. Body image and other insecurities affect sexual function, and have profound repercussions on self-esteem and self-concept. SCI causes difficulties in romantic partnerships, due to problems with sexual function and to other stresses introduced by the injury and disability, but many of those with SCI have fulfilling relationships and marriages. Relationships, self-esteem, and reproductive ability are all aspects of sexuality, which encompasses not just sexual practices but a complex array of factors: cultural, social, psychological, and emotional influences.

SCI usually causes sexual dysfunction, due to problems with sensation and the body's arousal responses. The ability to experience sexual pleasure and orgasm are among the top priorities for sexual rehabilitation among injured people.

Much research has been done into erection. By two years post-injury, 80% of men recover at least partial erectile function, though many experience problems with the reliability and duration of their erections if they do not use interventions to enhance them. Studies have found that half or up to 65% of men with SCI have orgasms, although the experience may feel different than it did before the injury. Most men say it feels weaker, and takes longer and more stimulation to achieve.

Common problems women experience post-SCI are pain with intercourse and difficulty achieving orgasm. Around half of women with SCI are able to reach orgasm, usually when their genitals are stimulated. Some women report the sensation of orgasm to be the same as before the injury, and others say the sensation is reduced.

Sexually induced sneezing is a phenomenon characterized by sneezing during orgasm or sexual arousal.

It is thought that people who suffer from this disorder, suffer from a dysfunction in the release of the chemical dopamine in the nucleus accumbens, the brain's primary reward center. This part of the brain is thought to play a role in pleasurable activities, including laughter, addiction, and music. Additionally, it is thought that depression, drug addiction, high levels of prolactin, low testosterone, and uses of certain medications might play a role in inhibiting dopamine. A spinal cord injury or chronic fatigue syndrome might also occasionally cause this disorder. Age may also be a cause of this disorder.

A sudden-onset sexual anhedonia can also be a symptom of sensory neuropathy, which is most commonly the result of pyridoxine toxicity (e.g., from large doses of vitamin B6 supplements).

In this case, the sexual dysfunction promptly resolves spontaneously once the B6 supplementation is stopped.

Increased serum prolactin (PRL) concentration in patients brains from psychiatric medicine can also affect sexuality.

Psychiatric medicine is known to cause the brain to form more dopamine receptors for the dopamine blocking effect. The normal amount of dopamine released during sex is insufficient to stimulate the larger number of dopamine receptors.

People with 46,XX testicular DSD have male external genitalia. They generally have small testes and may also have abnormalities such as undescended testes (cryptorchidism) or the urethra opening on the underside of the penis (hypospadias). A small number of affected people have external genitalia that do not look clearly male or clearly female (ambiguous genitalia). Affected children are typically raised as males and are likely to have a male gender identity.

The distinguishing characteristics of POIS are:

1. the rapid onset of symptoms after ejaculation;

2. the absence of any local genital reaction; and

3. the presence of an overwhelming systemic reaction.

POIS symptoms, which are called a "POIS attack", can include some combination of the following: cognitive dysfunction, aphasia, severe muscle pain throughout the body, severe fatigue, weakness, and flu-like or allergy-like symptoms, such as sneezing, itchy eyes, and nasal irritation. Additional symptoms include intense discomfort, irritability, anxiety, craving for relief, susceptibility to nervous system stresses (e.g. common cold), depressed mood, and difficulty communicating, remembering words, reading and retaining information, concentrating, and socializing. Affected individuals may also experience intense warmth or cold.

The symptoms begin shortly after or within a half hour of ejaculation.

The symptoms can last for several days, sometimes up to a week.

In some men, the onset of POIS is in puberty, while in others, the onset is in their twenties. POIS that is manifest from the first ejaculations in adolescence is called "primary type"; POIS that starts later in life is called "secondary type".

Many POIS sufferers report lifelong premature ejaculation, with intravaginal ejaculation latency time (IELT) of less than one minute.

Medications to treat high blood pressure, benign prostate hyperplasia, mood disorders, surgery on the prostate and nerve injury (which may occur in multiple sclerosis, spinal cord injury or diabetes).

A physical exam of the genitals is applied to ensure that there are no anatomical problems. The urine will be examined for the presence of semen. If there are no sperm in the urine, it may be due to damage to the prostate as a result of surgery or prior radiation therapy.