The title says it all. Anyone know the Straight Dope on condoms?
In condomeffectiveness.com (google is your friend) we find:
When used correctly, a male condom is about 98 per cent effective. This means that only about 2 in every 100 women would get pregnant in the course of a year.
Of course, this requires proper use, and most failure is associated with improper use, forgetfullness, too drunk to put one on, etc. Another studdy said 16% failure from slippage ( too loose???) and variously I recall news reports of real world experience that they are about 85% effective taking various reasons for failure into account, and the lifestyle of some people who use condoms rather than pill.
Genital warts (Human paopilomavirus [HPV] – illustrations NSFW) are a special case. The virus is transmitted via microabrasions to the skin by skin-to-skin sexual contact, including from tissues not covered by a condom (mucous membranes in mouth and anus, skin of scrotum, etc.) The Wikipedia article indicates 10-30% of the sexually active population carry HPV, and infection occurs from sexual contact with a HPV-carrying partner 70% of the time. No figure was given on the extent to which condoms protect against infection. This came up in the debates over Gardasil some time ago.
It’s probably neither the latest nor the most complete source of information out there, but since you asked for the Straight Dope:
Do condoms protect against STDs other than HIV?
Can HIV pass through the pores in latex condoms?
I can tell you from a personal viewpoint, condoms are effective against HIV. I know lots of HIV+ people with HIV- partners and I’ve never met one where the HIV- person got HIV. Now I’m sure that it happens do to incorrect use ect but when used properly condoms are an effective barrier to HIV.
The concern often arises because lambskin-type condoms are NOT effective against HIV but are good for pregnancy prevention.
Also remember use of proper lubricant makes a huge difference. If you use a latex condom and Vasoline, you’re gonna have problems. Certain lubes such as petrol jelly can break down or put holes in latex. KY-Jelly does not do this.
If you look at Japanese studies where condoms have been used for decades and decades and are part of a culture society the rate of pregnancy prevention is about 99%.
The thing is USED correctly. So many people don’t use them right.
As for stats the 99% refers to EACH sex act. If you have sex on Monday at 10pm and use a 99% effective against pregnancy condom, that means concerning THAT PARTICULAR ACT, you have a 99% of NOT getting her pregnant.
If you then decide to leave her and find another woman at 11:00pm on that same Monday, you have 99% chance of NOT getting her pregnant. It starts over with each sex act.
The thing about these numbers is they are (or should be) carefully controlled. The 99% effective assume that a woman is in a position to GET pregnant in the first place. She may not be. But that statistic doesn’t take that into consideration.
What that 99% is referring to is how many times in the exact same instances (not similar but exact) in a pool of study participants did it happen.
For example using the 99% rate. Let’s say this study had 1,000 people. That means when those 1,000 people had sex using the condoms EXACTLY as described in the study, of those 1,000 people 10 got pregnant.
HIV and other STDs are often treated like mysteries. The fact is you have to have them to get them. If you don’t have it, you can’t give it.
The Advocate Magazine pointed this out clearly with a startling statistic back in their article from 1999. It showed that you had less chance of getting HIV from having unprotected sex in Bangor, Maine, than you had from having protected sex in New York City.
At first glance this makes no sense, till you realize that NYC has 8 million plus tens of thousands of visitors and tourists. Bangor, ME has 35,000, of which there is very few HIV+ people.
But that statistic is meaningless if you break it down to a “per person basis.” It’s like the crime rate in NYC is lower than other cities, but there is usually MORE crime in sheer numbers because NYC is so much bigger.
So when you look at effectiveness rates, you have to use them with good sense.
As Mama from “Mama’s Family” said (regarding Naomi’s pregnancy), “There’s only one sure fire method. You keep to your side of the bed and when he moves over you tell him ‘NO’.”
Not true. Most statistics for birth control methods are actually giving a pregnancy rate per woman per year, not per individual sex act. So with the 98% effectiveness given above, out of 1000 women who use male condoms carefully and correctly for a year, 20 will become pregnant. 85% “real-world” effectiveness including all of the improper condom use means that 150 out of 1000 women will become pregnant.
According to a recent study, it’s a little more complicated than that.
No matter how many times they have sex during that year? I mean, that could vary A LOT. Are we talking about the averagely sexually active woman here? Is there such a being (or, if there is, do we know how horny she is)?*
Also, what is this incorrect way of using a condom that so many people are apparently indulging in? Short of really dumb stuff, like swallowing it, I can only really think of one way. I hope it has been the right one.
*And does anyone know her phone number?
Well, extrapolating from this source
It appears that’s for an average of 83 sex acts per year. (And a 0.024 percent per condom pregnancy rate, given perfect use. The same study the two percent number comes from quotes a 17.4% failure rate for “typical” use. That translates to a 0.21 percent per condom pregnancy rate.)
I remember reading (though I can’t find a cite at the moment) that not using a condom every time counts as using a condom improperly, at least for the purposes of whatever study. In other words, if a couple has said their primary birth control method is a condom, and they don’t use a condom and get pregnant, that counts as a failure due to improper use.
The same thing would apply to a birth control pill. If a female skips a day or two of the pill, and ends up pregnant, that would be due to improper use.
Yes, no matter how many times they have sex in a year. That’s why these studies groups are large - one woman who has sex three times a day and one women three times a year “cancel each other out”, so to speak. (That’s not really the right statistical way to look at it, but close enough for folk music.)
The most common incorrect condom use is probably poor lube choice, as mentioned. Not only using vaseline or massage oil on the vagina or condom itself, but also doing things like giving your partner a massage using massage oil and then not washing your hands with soap before putting the condom on and contaminating it with oil.
Another condom mistake is putting in on inside out. If you do this and then find the bugger won’t roll down without a lot of tugging, throw it away and use another! That tugging may have stretched it out, compromising the latex and promoting breakage. Too many men stretch it a bit, swear at it and then pull it off and flip it around. Now you’ve got weak latex and possibly even a bit of semen on the outside of the condom as well, especially if you’ve already come recently. (Pre-come, by the way, probably doesn’t have any semen in it, unless this is your second go round for the evening. Urine washes lingering sperm out of the urethra.)
It’s also important not to roll the condom on perfectly snug at the tip. Many users don’t seem to realize that the semen needs somewhere to go, and you need to leave a half inch or so loose at the tip or you risk a blow out.
Next, there’s a really stupid idea going around these days that if one condom is good, two are better. People seem to think that if one breaks, the other will work as a “back-up”. This is entirely false, and in fact the friction that results from “double bagging” increases the chances that both condoms will break.
Finally, for a few men, they’re just using the wrong size condoms, increasing the risks of the condom slipping off or breaking. Most guys don’t have to worry about this, but if you’re very large or very small, buy the specialty condom sized to match.
With very large studies and good statistics, you don’t have to worry about individual variability. So, yeah, that’s for the average woman. Presumably the yearly risk of pregnancy goes up with every sex act.
Though it might be a different situation with hormonal birth control – maybe there are just 1% of women who do not respond to the pill as well, so that risk of pregnancy is not correlated with frequency of sex.
And there are lots of ways to mess up condom use. An air bubble in the tip will make it more likely to break. Or it’ll slip off and neither partner notices or cares enough to stop. After ejaculating, if the man doesn’t pull out while still hard condoms will leak at the base.
ETA: What WhyNot said.
I’d assume that the most common “incorrect” way is - “let’s mess around a little…maybe just a few thrusts, *then *I’ll put on the condom”.
Other “incorrect” ways could be using them beyond the expiration date, using ones that have been weakened by being crushed in a wallet, using the wrong lubricant, etc.
Ooh, good ones! Eventually, we’ll come up with an exhaustive list!
Using condoms that have been left in a hot car/glovebox/wallet/tent, of course, is bad news. Heat degrades latex pretty quickly.