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← Male circumcision is a weapon in the sperm wars

glenister_m's Avatar Jump to comment 24 by glenister_m

Comment #189530 by SimUser

If a mans sexual partner has been recently with another man, then his (the primary partner) foreskin and the head of the penis will act as a sort of trow and bucket (very crude and barely accurate way of putting it) to scrape out the semen of the previous man, thus making it more likely that his sperm will be the ones with the greater chance to impregnate her.

You are correct. There are a couple of penis designs in nature. The human version which doesn't contain a bone, can act like a piston which sucks a competing males sperm out to give the male a better chance of fertilizing the female. The other version contains a bone, eg. mice, which is present because the sperm forms a hard plug to prevent foreign sperm from entering. The hard bony penis is used by competing males to separate the plug from the vaginal walls so that it falls out and the competing males sperm can enter.

Fri, 06 Jun 2008 12:03:00 UTC | #180039