# Condom is 85 to 98% effective - help me understand what this means

**URL:** <https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362>\
**Category:** Factual Questions\
**Created:** [August 26, 2006, 9:47pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362 "2006-08-26T21:47:21Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [August 26, 2006, 9:47pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/1 "2006-08-26T21:47:21Z")

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In this thread:

> **[antibiotics, sex, and the pill](https://boards.straightdope.com/sdmb/showthread.php?t=385731)**
>
> This is not a medical question. it is, somewhat, but I want ODDS. Today I began some antibiotics. I take them for 7 days. My very first one was this morn at 11 a.m. I had sex at noonish. We used condoms, for sure. The odds are okay that I will be...

titled  
antibiotics, sex, and the pill  
**twhitt** makes the claim:

> [@](#):
>
> Pretty much. When used properly, condoms are between 95 and 98% effective in preventing pregnancy; this means that only about 3 women in 100 will become pregnant each year if their partner uses male condoms. Cite. You’re quite unlikely to become pregnant.

The cite does not really help answer my question which is:

If we assume that 97% effectivness means that 3 women out of 100 using male type condoms will become pregnant within a year, what is the effectivness of unprotected vaginal sex, or how much ‘better’ is the correct use of a condom over not using it in preventing pregnancy.

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [August 26, 2006, 9:49pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/2 "2006-08-26T21:49:32Z")

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That should read 95-98% not 85%, mods if you are just itching for a task feel free to corret that, if not no biggie.

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**Author:** ![Garfield226](https://avatars.discourse-cdn.com/v4/letter/g/9e8a1a/32.png) [@Garfield226](https://boards.straightdope.com/u/Garfield226)\
**Post date:** [August 26, 2006, 9:55pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/3 "2006-08-26T21:55:01Z")

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> [@kanicbird](#):
>
> The cite does not really help answer my question which is:
> 
> If we assume that 97% effectivness means that 3 women out of 100 using male type condoms will become pregnant within a year, what is the effectivness of unprotected vaginal sex, or how much ‘better’ is the correct use of a condom over not using it in preventing pregnancy.

There are lots of numbers floating around out there (google “birth control statistics”), but [Planned Parenthood](http://www.plannedparenthood.org/pp2/portal/medicalinfo/birthcontrol/pub-birth-control-02.xml) has a fairly detailed list.

They say that using no method of birth control, 85 of 100 women become pregnant within a year.

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**Author:** ![crazyjoe](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@crazyjoe](https://boards.straightdope.com/u/crazyjoe)\
**Post date:** [August 26, 2006, 11:57pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/4 "2006-08-26T23:57:24Z")

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Yes, if you’re completely ignoring any sort of BC methods, you can get pregnant fairly easily (depending on your situation, of course). If you practice the “rhythm” method, you can get the effectiveness up to about 80% (20 out of 100 women become pregnant) or so. Using some other biological methods, you can get even closer to that 95% figure, but you have to be fairly well educated about the signs to look for.

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**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\
**Post date:** [August 27, 2006, 5:08am UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/5 "2006-08-27T05:08:46Z")

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> [@kanicbird](#):
>
> If we assume that 97% effectivness means that 3 women out of 100 using male type condoms will become pregnant within a year, what is the effectivness of unprotected vaginal sex, or how much ‘better’ is the correct use of a condom over not using it in preventing pregnancy.

Sancho never wears a condom, skewing the statistics a bit.

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**Author:** ![MandaJo](https://avatars.discourse-cdn.com/v4/letter/m/ac91a4/32.png) [@MandaJo](https://boards.straightdope.com/u/MandaJo)\
**Post date:** [August 27, 2006, 12:47pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/6 "2006-08-27T12:47:08Z")

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I want to see the theoretical vs. actual stats for abstinence. Proponents of abstenince always talk about how the other BC methods that people use aren’t really as effective as claimed because people make mistakes, get sloppy, etc, while abstinence remains 100% effective. Well, that’s because when there is a user error in the “abstinence” technique, we don’t call it “failed abstinience”, we call it “unprotected sex”. But I don’t see how planning to use a condom and then, in a momment of passion, forgetting, is any different than planning not to have sex and then, in a momment of passion, forgetting. And I suspect the latter happens at least as often as the former.

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [August 27, 2006, 1:50pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/7 "2006-08-27T13:50:15Z")

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> [@Manda JO](#):
>
> But I don’t see how planning to use a condom and then, in a momment of passion, forgetting, is any different than planning not to have sex and then, in a momment of passion, forgetting.

I don’t take it like that, not using a condom is unprotected sex. I would take the actual numbers for condoms being lower then the maximum perfect numbers would include things like using one that was damaged while opening, or just putting it on for the ‘ending event’ while most of the sex was w/o one, or reusing one.

Also I disagree with:

> [@](#):
>
> in a momment of passion, forgetting, is any different than planning not to have sex and then, in a momment of passion, forgetting. **And I suspect the latter happens at least as often as the former.**

People who are commited to abstinance may engage in outercorse activities (oral, mutual masterbation, ect.) if things go that far, but people who are used to sex are far more likely to take a chance if they don’t have a condom on hand, or re-use one.

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [August 27, 2006, 2:03pm UTC](https://boards.straightdope.com/t/condom-is-85-to-98-effective-help-me-understand-what-this-means/370362/8 "2006-08-27T14:03:43Z")

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> [@kanicbird](#):
>
> People who are commited to abstinance may engage in outercorse activities (oral, mutual masterbation, ect.) if things go that far, but people who are used to sex are far more likely to take a chance if they don’t have a condom on hand, or re-use one.

[correction]The above is my suspicions only, not that I know it to be a fact[/correction]
