It is estimated to occur in one out of five million live births, and usually accompanied hindgut or anorectal duplication and the patient had a higher risk of spina bifida.

The first reported case of PD was reported by Johannes Jacob Wecker in 1609 [1]. Penile duplication is a normal finding in some animal species; like in male snakes, lizards and Sugar Glider which is a small, nocturnal, arboreal marsupial native to Australia, where each possessing a pair of penis-like organs, while mammals and birds are stuck with only one Fig. 11.1.

Duplication of the penis is a rare anomaly with a wide range of appearances from a small accessory penis to complete organ duplication. In some cases, each phallus has only one corporal body and urethra, whereas others seem to be a variant of twinning, with each phallus having two corpora cavernosa and a separate urethra with or without bladder duplication (Fig. 11.2). The penises usually are unequal in size and lie side by side, but very rarely the other moiety lies beneath the first one in a sagittal plane (Fig. 11.3), or ectopic in the buttocks or over the sacrum, but in such cases the duplication is not true and the rudimentary extra penis is devoted from urethra and corporal tissues, but carrying the morphological look of the penis with a shaft and glans (Figs. 11.4 and 11.5).

Partial duplication of the penis may be manifested as a duplicated glans penis without any intervening urethra (Fig. 11.6).

Penile duplication should be differentiated from the rare cases of bifid penis, which is mainly seen in association with cases of bladder exstrophy, in such cases the bifid penises are asymmetrical and may be associated with bifid scrotum, in female a bifid clitrois is the counter presentation (Fig. 11.7).