the rate of withdrawal for perfect use is 4%. However, on that website, it says that the 4% who do get pregnant can include men that did not know they did ejaculate. In addition to that, according to this website:
all the way at the bottom, it says there is a 0.0025% of getting pregnant from pre-cum. In one year, couples have sex about 112 times. Since 4% pregnant for withdrawal is measured for a year, 112x0.000025=0.0028, about 0.003 percent. Based on everything above, if every single person who was sampled for the perfect withdrawal survey knew for sure they did NOT ejaculate inside the vagina, wouldn't the actual percentage be about 0.003?
Posts: 2 | Registered: Aug 2011
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When you did that multiplication, you didn't shift the decimal point to the right to get the resulting percentage. .3%, not .003%.
That isn't terribly important though, because you started with the annual rate in the first place. The .0025% rate of pregnancy resulting from pre-cum is a per-year rate, not per-incident, so there's no need to multiply it out by a hypothetical number of times that a couple has sex in a year.
Per-incident rates are completely unhelpful for thinking about risk of pregnancy. You are not reducing your pregnancy risk by only having sex once, or once in a while.
If I had to guess, I'd say that those men who didn't realize they ejaculated were likely to feel sure that they didn't, so they'd report themselves in the "absolutely certain I didn't ejaculate" group.
Posts: 129 | From: Boston | Registered: Mar 2011
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