I completely agree and I know that its not possible to get pregnant from cumming in the ass itself, I was only speaking of the risk of leakage into the vag and also was wondering about nutrient absorption of the semen in the colon but you answered that so thanks.
very informative thanks PineMan. My girl gets very wet during anal and thats why i was concerned since leakage from the anus or while i pull out after cumming inside her ass may contact the vagina/juices and slowly travel up the vag canal, however I have read that the vag is highly acidic at the opening which kills sperm/semen which is basic and the farther inside the canal the more chances the sperm will survive since the acidity decreases as you travel deeper.
Here's what I remember from Highschool biology class. From the time a sperm cell leaves the penis to the time it fertilizes an egg is roughly the equivelent of a human swimming from Seattle, Washington to San Diego, California. The Female body recognizes these cells as intruders and the immune system releases white blood cells to fight the little bastards. Then I shit you not this sounds like a dumb feminist joke but it isn't some of those sperm cells try to fertilize the white blood cells that the female body just sent to kill them (even before birth some men will fuck anything). That is just with vaginal sex imagine all of that happening after the sperm has been unloaded into an anus first then dripping out of the asshole and back up into the vaj chances of those little swimmers surviving are slim. Stay Brown, Rev J