I was taught that condoms were useless against HIV

[Lord_Ashtar]

As a teenager, I was always told that since HIV was about a quarter of the size of the microscopic holes in condoms, that they were useless against AIDS. This site provided by Homebrew in this thread suggests that either no longer, or never was, true.

What’s the straight dope?

Please leave the Catholic Church bashing to the above linked thread. Thanks.

[Zsofia]

Well, a lambskin condom is not effective against HIV. How old are you?

[Call_me_Frank]

http://www.straightdope.com/classics/a940506.html

Granted, it’s nearly 11 years old, but you can’t beat the source…

[capybara]

Did you go to an unusual-format school (Catholic or some other non-public school system)? I went to a rural public school (late 1980s) and we were taught that condoms were effective (and other birth control was not), but not to use lambskin condoms or use oil-based lubes. And we wuz in the sticks.

[Lord_Ashtar]

So they don’t prevent it, but they greatly lower the risk of contracting it?

[Lord_Ashtar]

@capybara

Did you go to an unusual-format school (Catholic or some other non-public school system)? I went to a rural public school (late 1980s) and we were taught that condoms were effective (and other birth control was not), but not to use lambskin condoms or use oil-based lubes. And we wuz in the sticks.

I went to high school in Northern Virginia. I’m sure my father was the one to tell it to me.

[Cartooniverse]

I love Unca Cecil as well as the next Doper, but around these parts if I want the Straight Dope on matters pertaining to health, I go to the Centers for Disease Control-CDC, based in the US, in Atlanta, Georgia.

Go. Read.

Cartooniverse

[TonyF]

@Lord Ashtar

So they don’t prevent it, but they greatly lower the risk of contracting it?

Something like that. Keep in mind that they often must factor other issues into the equation - e.g. improper use and, of course, legal aspects. They may very well prevent HIV transmission in ideal circumstances - but it’s best not to take the chance if you know better anyhow.

[Zsofia]

Also the jury is still out on exactly how high the risk of transmission during, say, oral sex is. But for penetrative sex, a properly used condom that does not break is good HIV prevention, I think most authorities who aren’t speaking for the Catholic church would say. That, of course, means perfect use, with appropriate method and water or silicone based lube, pulling out while holding the condom immediately after ejaculation, nobody involved has cuts or sores or anything like that, etc.

[Tentacle_Monster]

I think I’ve heard of condoms made of polypropylene or some other plastic. And IIRC, they’re nonporous. So why aren’t these more prevalent?

[elfbabe]

@Lord Ashtar

So they don’t prevent it, but they greatly lower the risk of contracting it?

I would say that they do prevent it, but not perfectly. It’s just an issue of phrasing, really, but saying they don’t prevent it makes it sound like they don’t actually do anything.

[threemae]

@Lord Ashtar

As a teenager, I was always told that since HIV was about a quarter of the size of the microscopic holes in condoms, that they were useless against AIDS. This site provided by Homebrew in this thread suggests that either no longer, or never was, true.

What’s the straight dope?

Please leave the Catholic Church bashing to the above linked thread. Thanks.

When I was in my HS health class, one of those wet-behind the ears, “heard it from a scientist” types emphatically informed me that it wouldn’t do us any good to check a condom after sex by filling it with water (that’s kinda true), “because a sperm is a quarter the size of a water molecule.” I asked to clarify and make sure she didn’t mean a water droplet, but she assured me, no, definitely smaller than a water molecule.

:rolleyes

[matt_mcl]

From the CDC, cited above:

A commonly held misperception is that latex condoms contain “holes” that allow passage of HIV. Although this may be true for natural membrane condoms, laboratory studies show that intact latex condoms provide a continuous barrier to microorganisms, including HIV, as well as sperm.

In other words, semen will not pass through the intact wall of a condom under any circumstances, nor will anything in it. The wobble in the numbers is probably due to tears, spills, and (most probably) exaggerated consistency in using condoms.

[GorillaMan]

Possibly the teaching of the OP was a garbling of the message that condoms aren’t sufficient to protect against all STDs?

[Jervoise]

Perhaps the OP has been listening to misinformation spread by certain ranking members of the Catholic clergy:

The president of the Vatican’s Pontifical Council for the Family, Cardinal Alfonso Lopez Trujillo, told the programme: "The Aids virus is roughly 450 times smaller than the spermatozoon. The spermatozoon can easily pass through the ‘net’ that is formed by the condom.

Of course, this is rubbish:

The [World Health Organisation] says “consistent and correct” condom use reduces the risk of HIV infection by 90%. There may be breakage or slippage of condoms - but not, the WHO says, holes through which the virus can pass .

Scientific research by a group including the US National Institutes of Health and the WHO found “intact condoms… are essentially impermeable to particles the size of STD pathogens including the smallest sexually transmitted virus… condoms provide a highly effective barrier to transmission of particles of similar size to those of the smallest STD viruses”.

… not that that will stop some people:

The Vatican’s Cardinal Trujillo said: “They are wrong about that… this is an easily recognisable fact.”

:rolleyes:

[Arwin]

@GorillaMan

Possibly the teaching of the OP was a garbling of the message that condoms aren’t sufficient to protect against all STDs?

No. Quite simply it’s as above - the condom may tear or slip off, and then you may be in trouble. But other than that, it’s safe. The stuff that Lord Ashtar learnt is nonsense.

And even though he asks not to bash the Roman Catholic Church, this is one instance where it seriously deserves bashing.

[Colibri]

@elfbabe

I would say that they do prevent it, but not perfectly. It’s just an issue of phrasing, really, but saying they don’t prevent it makes it sound like they don’t actually do anything.

Yes. In the same sense seat belts may be said to prevent death or serious injury in auto accidents. This doesn’t mean that seat belts are absolutely infallible in stopping all deaths and injuries, just that many fewer people are killed or injured when they are used, so that many potential deaths are prevented. In the same sense, condom use prevents (many potential cases of) HIV transmission.

[Lord_Ashtar]

@Colibri

Yes. In the same sense seat belts may be said to prevent death or serious injury in auto accidents. This doesn’t mean that seat belts are absolutely infallible in stopping all deaths and injuries, just that many fewer people are killed or injured when they are used, so that many potential deaths are prevented. In the same sense, condom use prevents (many potential cases of) HIV transmission.

There we go. That’s the kind of analogy I needed. Thanks.

[Loopydude]

I’d put in stronger terms: Parachutes, when properly handled and utilized, are very good at keeping skydivers from going splat. When a parachute works as specified (which is in the vast majority of cases), a skydiver using the parachute will not go splat. Period.

[WhyNot]

@Tentacle Monster

I think I’ve heard of condoms made of polypropylene or some other plastic. And IIRC, they’re nonporous. So why aren’t these more prevalent?

Last I knew, which was about 5 years ago, they had not undergone the rigorous testing required to label their condoms as preventing HIV transmission. Theoretically, they should do the job fine, but there were not tests to back it up. Maybe there are by now.