Male genital morphology and function: an evolutionary perspective.
OBJECTIVE
The genitals are at the forefront of evolution. Advantageous features of genital form and function determine which individuals pass their genes to future generations. The male genitalia are primarily for sperm deposition but additional functions of the penis and its accessory structures are being identified.


METHODS
The literature regarding genital evolution was reviewed.


RESULTS
This review explains key theories regarding the mechanisms of genital evolution. Also discussed are the anatomical and functional adaptations among different species that have evolved to optimize fertilization success. Finally, these evolutionary influences are discussed in the context of clinically relevant human genital morphology and function.


CONCLUSIONS
The function of the genitalia extends beyond simple sperm transfer. Genital morphology evolves to provide the primary and secondary functionality that is critical for successful mating. By considering the form and function of human genital morphology in an evolutionary context we gain not only an appreciation for its design, but also the potential for a deeper understanding of our treatment goals.
Simmons
Matthew N
MN
Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. simmonm2@ccf.org
Jones
J Stephen
JS
D000818:Animals; D005298:Fertility / Q000502:physiology*; D005837:Genitalia, Male / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D008297:Male