1

Erotic pleasure, especially via the ridged band and Meissner's corpuscles

2

Acts as a rolling bearing in intercourse and masturbation

3

Prevents dyspareunia (painful intercourse)

4

Stimulates partner's genitalia, giving erotic pleasure

5

Supplies skin to cover the shaft in erection and prevent tightness

6

Stores pheromones and releases them on arousal

7

Stores, releases and helps distribute natural lubricants ("smega" and pre-ejaculatory fluid)

8

Makes the glans a visual signal of sexual arousal

9

Provides a seal against the vaginal wall to contain semen

10

Prevents the glans becoming keratinised, and keeps it soft and moist

11

Protects the thin-skinned glans against injury

12

Protects the nerves of the glans, retaining their erotic function

13

In infancy, protects the urethra against contamination, meatal stenosis, (and UTIs?)

14

Provides lysosomes for bacteriostatic action around the glans

15

Pigmented, it protects the unpigmented glans against sunburn

16

Vascular (rich in blood vessels that bring heat to the tissues), it protects the less vascular glans against frostbite, as Sir Ranulph Fiennes found on his epic transpolar walk.

17

Provides skin for grafts to burnt eyelids, reconstructive surgery, etc.

18

"The foreskin is important embryologically in the formation of the end of the penis and the urethra. If there is no foreskin the urethral opening is not at the end of the penis where it should be, but somewhere on the underside of the penis (hypospadius [sic])." - Dr Edgar Schoen (!) (but he claims that is its only function)

19

Holds absorbant tissue in place after urethral surgery, in case of minimal incontinence, etc.

20

Storage of contact lenses, smuggled jewels, etc. - not all recommended uses ...

... it would be preposterous to suggest that babies should be circumcised to prevent them doing this as adults, but such is the irrational pressure to circumcise, there are those who will.