11) Smoking can shorten your man-hood by as much as a centimeter.
Erections are all about good bloodflow, and lighting up calcifies blood vessels, stifling erectile circulation.
12) The foreskin has an abundance of Langerhans cells, which are immune cells that are infiltrated by HIV.
This may explain why circumcised men in Africa have a 60% lower rate of HIV infection from heterosexual intercourse.