A micropenis or microphallus is an unusually small penis. A common criterion is a dorsal (measured on top) penile length of at least 2.5 standard deviations smaller than the mean human penis size for age. A micropenis is stretched penile length equal to or less than 1.9 cm (0.75 in) in term infants, and 9.3 cm (3.67 in) in adults. The condition is usually recognized shortly after birth. The term is most often used medically when the rest of the penis, scrotum, and perineum are without ambiguity, such as hypospadias. Traditionally, a microphallus describes a micropenis with hypospadias. Micropenis incidence is about 1.5 in 10,000 male newborns in North America.