An abnormally shaped penis ( abnormal penis ) may be due to a developmental defect from birth, a serious injury to the penis or a couple of rare diseases. It is quite common for there to be slight curvature to the left or right, and an upward curve in the erect penis is totally normal.
Hypospadias is a developmental abnormality in which some boys are born with the opening of the urethra (urine tube) on the underside or at the base of the penis instead of the end. It can usually be surgically corrected.
Peyronie disease is an abnormal curvature of the penis caused by scarring, poor blood supply, infection or other damage to the erection sustaining blood sacs on only one side of the organ.
Lichen sclerosis is a scarring and thickening of the skin on one side of the penis, caused by infection or injury to the penis. It causes a sideways curve to the penis that may be painful during an erection.
Smith-Lemli-Opitz syndrome is an inherited disorder that causes drooping of the eyelids, a narrow forehead, intellectual disability, hypospadias (see above), prominent nostrils and webbed toes.
Diphallia is an extremely rare (one in 5 million) condition in which two penises are present with urine discharging through the urethral opening between them at their bases. These penises do not function normally.