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.

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.

Penetrating and blunt traumas combined make up approximately 90% of all civilian penile injuries (45% each), with burns and other accidents making up the remaining 10%.

It is a rare condition, with only approximately 60 cases reported as of 1989, and 75 cases as of 2005. However, due to the stigma of intersex conditions and the issues of keeping accurate statistics and records among doctors, it is likely there are more cases than reported.

Even with successful surgery, patients may have long-term problems with:

- incontinence, where serious usually treated with some form of continent urinary diversion such as the Mitrofanoff

- depression and psycho-social complications

- sexual dysfunction

Buried penis (also known as hidden penis) is a congenital or acquired condition, in which the penis is partially or completely hidden below the surface of the skin. It can lead to obstruction of urinary stream, poor hygiene, soft tissue infection, phimosis, and inhibition of normal sexual function. Congenital causes include maldevelopment of penile shaft skin, whereas acquired conditions include morbid obesity, overlaying abdominal fat, or penile injury. Adults with a buried penis will either live with their condition or undergo weight-loss programs. However, weight-loss programs are slow and often do not "unbury" the penis; furthermore, poor hygiene from pooling of urine can lead to soft tissue infection. Patients will eventually need definitive reconstructive surgery and more urgent surgery if infection is present. Surgeons who manage this condition are either reconstructive urologic surgeons or plastic surgeons.

The causes of penile injury are mostly the same as other causes of trauma; however, penile injury is more likely to occur during sexual intercourse and masturbation than other traumas. Nocturnal erections and sleeping positions can be another cause of penile injury. Industrial and automobile accidents can also cause penile injury. Self-injury may also affect the penis.

Webbed penis, also called penis palmatus or penoscrotal fusion, is an acquired or congenital condition in which the scrotal skin extends onto the ventral penile shaft. The penile shaft is buried in scrotum or tethered to the scrotal midline by a fold or web of skin. The urethra and erectile bodies are usually normal. Webbed penis is usually asymptomatic, but the cosmetic appearance is often unacceptable. This condition may be corrected by surgical techniques.

In the congenital form, the deformity represents an abnormality of the attachment between the penis and the scrotum; the penis, the urethra, and the remainder of the scrotum typically are normal.

Webbed penis may also be acquired (iatrogenic) after circumcision or other penile surgery, resulting from excessive removal of ventral penile skin; the penis can retract into the scrotum, resulting in secondary phimosis (trapped penis).

One procedure for webbed penis is the insertion of a subcutaneous soft silicone implant under the penile skin. The procedure was developed by urologist James J. Elist.

Procedure for buried penis is the insertion of a subcutaneous soft silicone implant under the penile skin. The procedure was developed by urologist James J. Elist.

When an infant is born with PSH, the most difficult management decision has often been the sex assignment, since genitalia with this degree of ambiguity do not resemble either sex very well with respect to looks or function. Many infants with PPHS have been assigned and raised as female despite presence of testes and XY chromosomes.

Nearly all parents of infants with PPSH are offered surgical reconstruction, to either further masculinize or feminize the external genitalia.

Treatment with testosterone postnatally does not close the urethra or change the malformation, but in some cases may enlarge the penis slightly.

The main treatment for isolated epispadias is a comprehensive surgical repair of the genito-urinary area usually during the first 7 years of life, including reconstruction of the urethra, closure of the penile shaft and mobilisation of the corpora. The most popular and successful technique is known as the modified Cantwell-Ransley approach. In recent decades however increasing success has been achieved with the complete penile disassembly technique despite its association with greater and more serious risk of damage.

A bifid penis (or double penis) is a rare congenital defect where two genital tubercles develop.

Historically, males born with a bifid penis often underwent sex reassignment surgery, due to the difficulty of penile reconstruction. They were raised as girls, and often had reconstructive surgery to make them phenotypically female, coupled with female hormone replacement therapy. However, in recent years, this practice has fallen under heavy scrutiny due to both a high frequency of sexual dysfunction in gender converted children, and more advanced penile reconstruction techniques.

Many male marsupials naturally have a bifid penis, with left and right prongs that they insert into multiple vaginal canals simultaneously.

Paraphimosis can be avoided by bringing the foreskin back into its normal, forward, non-retracted position after retraction is no longer necessary (for instance, after cleaning the glans penis or placing a Foley catheter). Phimosis (both pathologic and normal childhood physiologic forms) is a risk factor for paraphimosis; "physiologic" phimosis resolves naturally as a child matures, but it may be advisable to treat "pathologic" phimosis via long-term stretching or elective surgical techniques (such as preputioplasty to loosen the preputial orifice or circumcision to amputate the foreskin tissue partially or completely).

The foreskin responds to the application of tension to cause expansion by creating new skin cells though the process of mitosis. The tissue expansion is permanent. Non-surgical stretching of the foreskin may be used to widen a narrow, non-retractable foreskin. Stretching may be combined with the use of a steroid cream. Beaugé recommends manual stretching for young males in preference to circumcision as a treatment for non-retractile foreskin because of the preservation of sexual sensation.

Paraphimosis can often be effectively treated by manual manipulation of the swollen foreskin tissue. This involves compressing the glans and moving the foreskin back to its normal position, perhaps with the aid of a lubricant, cold compression, and local anesthesia as necessary. If this fails, the tight edematous band of tissue can be relieved surgically with a dorsal slit or circumcision. An alternative method, the Dundee technique, entails placing multiple punctures in the swollen foreskin with a fine needle, and then expressing the edema fluid by manual pressure. According to Ghory and Sharma, treatment by circumcision may be elected as "a last resort, to be performed by a urologist". Other experts recommend delaying elective circumcision until after paraphimosis has been resolved.

Aphallia has no known cause. It is not linked to deficient hormone amounts or action, but rather to a failure of the fetal genital tubercle to form between 3 and 6 weeks after conception. The urethra of an affected child opens on the perineum.

It is considered a form of 5-alpha-reductase deficiency involving SRD5A2.

Paraphimosis is usually caused by medical professionals or parents who handle the foreskin improperly: The foreskin may be retracted during penile examination, penile cleaning, urethral catheterization, or cystoscopy; if the foreskin is left retracted for a long period, some of the foreskin tissue may become edematous (swollen with fluid), which makes subsequent reduction of the foreskin difficult.

Penile fracture is a medical emergency, and emergency surgical repair is the usual treatment. Delay in seeking treatment increases the complication rate. Non-surgical approaches result in 10–50% complication rates including erectile dysfunction, permanent penile curvature, damage to the urethra and pain during sexual intercourse, while operatively treated patients experience an 11% complication rate.

In some cases, retrograde urethrogram may be performed to rule out concurrent urethral injury.

Penile fracture is a relatively uncommon clinical condition. Vaginal intercourse and aggressive masturbation are the most common causes. A 2014 study of accident and emergency records at three hospitals in Campinas, Brazil, showed that woman on top positions caused the greatest risk with the missionary position being the safest. The research conjectured that when a woman is on top, she usually controls the movement and her entire body weight lands on the erect penis. She is not able to interrupt movement when the penis suffers a misaligned penetration. Conversely, when the man is controlling the movement, he has better chances of stopping the penetration thrusts in response to pain, minimizing harm to himself.

The practice of "taqaandan" (also "taghaandan") also puts men at risk of penile fracture. Taqaandan, which comes from a Kurdish word meaning "to click", involves bending the top part of the erect penis while holding the lower part of the shaft in place, until a click is heard and felt. Taqaandan is said to be painless and has been compared to cracking one's knuckles, but the practice of taqaandan has led to an increase in the prevalence of penile fractures in western Iran. Taqaandan may be performed to achieve detumescence.

It is also known that disruption of the endocrine system by certain chemicals adversely affects the development of the reproductive system and can cause vaginal cancer. Many other reproductive diseases have also been link to exposure to synthetic and environmental chemicals. Common chemicals with known links to reproductive disorders include: lead, dioxins and dioxin-like compounds, styrene, toluene, BPA (Bisphenol A) and pesticides.

Examples of congenital abnormalities of the reproductive system include:

- Kallmann syndrome - Genetic disorder causing decreased functioning of the sex hormone-producing glands caused by a deficiency or both testes from the scrotum.

- Androgen insensitivity syndrome - A genetic disorder causing people who are genetically male (i.e. XY chromosome pair) to develop sexually as a female due to an inability to utilize androgen.

- Intersexuality - A person who has genitalia and/or other sexual traits which are not clearly male or female.

Hypospadias is among the most common birth defects in the world and is said to be the second-most common birth defect in the male reproductive system, occurring once in every 250 males.

Due to variations in the reporting requirements of different national databases, data from such registries cannot be used to accurately determine either incidence of hypospadias or geographical variations in its occurrences.

A chordee may be caused by an underlying condition, such as a disorder of sex development or an intersex condition, or from a complication of circumcision, though some medical professionals do not consider it to be true chordee because the corporal bodies are normally formed. However, not all congenital chordee includes abnormal corpora, and case reports of damage to the corpus cavernosum from circumcision are noted in the literature; particularly as a complication of local anesthetic.

Inflammation has many possible causes, including irritation by environmental substances, physical trauma, and infection such as bacterial, viral, or fungal. Some of these infections are sexually transmitted diseases.

It is less common among people who are circumcised as in many cases the foreskin contributes to the disease. Both not enough cleaning and too much cleaning can cause problems. Diabetes can make balanitis more likely, especially if the blood sugar is poorly controlled.

It is important to exclude other causes of similar symptoms such as penile cancer.

Extravasation of urine due to blunt renal trauma or ureteral obstruction can lead to the formation of an urinoma.

Chordee () is a condition in which the head of the penis curves downward or upward, at the junction of the head and shaft of the penis. The curvature is usually most obvious during erection, but resistance to straightening is often apparent in the flaccid state as well. In many cases but not all, chordee is associated with hypospadias. This is not the same condition as Peyronie's disease, which involves curvature of the shaft of the penis most commonly due to injury during adult life.