Monday, May 30, 2011

Why is the G-spot still such a mystery?

A couple of weeks ago I called out a woman on Dan Savage's podcast who asserted that we know exactly what the structure of the G-spot is, that all women have it, and that every woman can ejaculate. I called her out because scientists haven't reached a consensus on the G-spot. They're not sure what the heck it is, how variable it is in women, or if it even exists at all.

But calling her out made me wonder: Why is the G-spot still such a mystery?

To put it simply? The current research sucks.

And that's not just my personal opinion. The Journal of Sexual Medicine did a big review of G-spot research at the end of 2010 (1). Their conclusion?
Although a huge amount of data (not always of good quality) have been accumulated in the last 60 years, we still need more research on one of the most challenging aspects of female sexuality.
For those of you who don't speak science-ese, allow me to translate: A lot of this data is crap, and therefore we don't know what's going on.

After even the briefest overview of the literature, you start to understand why we're so confused. For example, let's look at two very popular G-spot papers from very different camps.

First, the "It's all in your head!" camp. This is the less popular view, but there are some researchers who think the G-spot is nothing more than the placebo effect. The main study they have supporting this was done by Andrea Burri in 2010 (2). They did a twin study and claimed to find no genetic correlation for the G-spot - that is, if a woman had a G-spot, her twin was not more likely to also have a G-spot. It spread like wildfire in the media, and was even picked up by xkcd:
Except this study was a piece of crap.

For one, they did absolutely no physiological studies. How did they know if a woman had a G-spot, then? Why, they simply asked them! In the most leading, biased way possible (emphasis mine):

“Do you believe you have a so called G spot, a small areas the size of a 20p coin on the front wall of your vagina that is sensitive to deep pressure?”

If we ignore how poorly worded that question was, it still is not going to test genetic correlation of having a G-spot. Relying on personal opinion for physiological data is frankly ridiculous - would we determine how many lobes a liver has by asking people what they believe to be true? What they're actually testing is if someone's personal opinion about G-spots is genetic! Someone could think she doesn't have a G-spot, but still have the exact same physiological reactions as her sister.

The other huge flaw of the study was that it didn't take into account sexual practices. What if one twin only has sex in the missionary position, while the other is purposefully trying out stuff to reach her "so-called" G-spot? It's wrong to assume that all types of sex produce the same time of stimulation. The researchers seemed somewhat aware of this, because they excluded bisexuals and lesbians...because they tend to have more digital sex.

Wait, what? So you have a group of people having the type of sex that, from conventional wisdom, is more likely to stimulate the "G-spot" - and you leave them out? Why not test to see if that conventional wisdom is actually right?

Well, maybe because the lead researcher is "anxious to remove feelings of "inadequacy or underachievement" that might affect women who fear they lacked a G-spot." That's certainly a noble cause, since women shouldn't feel inadequate if they lack a G-spot...but it also certainly biases your research if you're searching for a particular answer to support your world-view. Not to mention just swaps the stigma onto women who are told they're being delusional based on crappy data.

I've been harping on the G-spot deniers, but the research on the other side is just as bad. I looked up the paper by Florian Wimpissinger that's often cited as showing that female ejaculation is way more similar to semen than urine (3).

Yes, I had a good giggle that his name was Wimpissinger.

Anyway, this study looks very impressive on the surface. They did ultrasounds that found prostate-like structures in women! And urethroscopy that found a duct-like thingy! And biochemical analysis that showed it wasn't urine! Doesn't that sound fancy and

Except they did a crappy job at those things.

Their ultrasound was so blurry and inconclusive that the article is immediately followed by a letter from concerned researchers saying "Dude, you totally misread that ultrasound. That's a smudge, not prostate tissue." And their response is basically "No, we're right!" Not the best sign.
Maybe a prostate-like thingy.

But you know what's a bigger problem then their possibly blurry ultrasound?

They had a sample size of two women who could ejaculate, and no control women.

Sample size of two.

No controls.

So while you can say some women may have a prostate-like structure (assuming their ultrasound doesn't suck), you can't say they all do. Because you tested two women out of 3 billion. What do the non-ejaculators look like? What do the women who think they don't have G-spots look like? Humans are highly variable - height, skin color, breast size - the same could definitely apply to G-spots.

This is especially important in their biochemical study. They took ejaculate and urine samples from both women and compared them to the ejaculate from men using biochemical assays. They didn't have a urine sample from men or non-ejaculating women to compare it to as a control. And for the second woman, they didn't even do 5/9 of the tests! So basically they have a couple tests that vaguely show female ejaculate is more ejaculate-like than urine-like. I say vaguely because they didn't do any sort of statistical analysis to see if this is significant or due to random chance - probably because they have a freaking sample size of two.

So from looking at these two important studies, it's crystal clear why we don't know what's going on yet. The research just isn't high quality.

But why haven't scientists figured this out by now? How is it that we can track every individual cell in a developing worm, but we can't tell if a structure is there or not in women? How is it that we know genetic variation at millions of sites in the genome across human populations, but we don't know structural or physiological variation of an often discussed phenomena?

For one thing, the G-Spot is probably complicated. If I had to put my money on a hypothesis, I'd guess the G-spot is actually a combination of structures - maybe the Skene's glands, the internal part of the clitoris, prostate-like tissue, or vaginal thickness. And I'd guess that it's variable across women - either due to genetics or hormonal context during development. And when something is complicated, it's a bit harder to figure out.

Part of the problem of getting a really good study is that sexual science is somewhat of an echo chamber. Almost all of the research is published in the Journal of Sexual Medicine, and almost all of the reviewers of papers are part of the same little group. They don't have random molecular biologists reviewing their papers and weeping at their sample size, or screaming "Why didn't you just do a mass spec run?!" There's a reason why this stuff isn't getting published in PNAS, Science, or Nature - maybe partly due to blushing editors, but mainly due to quality.

Another problem is that a good study of something complicated calls for thousands of samples - and it's not easy to find thousands of women willing to participate in such a study. That's not just because of puritanical views, though that's definitely a contributing factor. Women have been historically mistreated under the guise of medicine, especially within the realm of sexual medicine. Treatments for hysteria, forced sterilization - those things may be in the past, but they still linger in people's memories.

But even if you had the best scientists and a thousand volunteers, a lot of it boils down to the politics of science - especially the politics of the science of sex. In the US, the type of research that's being done is the type of research that's being funded - mostly from the government. And when you look at these studies, almost none of them are coming from the US - the two I mentioned were from the UK and Austria. Our puritanical views make it less likely that a massive G-spot study is going to be funded to put this question to rest.

I'm not trying to be overly patriotic, but the US produces some of the highest quality scientific research in the world. And when it's too scared to finance the investigation of women's sexuality, it's no wonder we're left in the dark.

Yet somehow there's no shortage of money so men can keep having erections. Funny how that works.

So the next time someone claims to know exactly what a G-spot is - especially when they're trying to sell you something - think of the science behind it. And remember, it's okay for science to say "I don't know - yet."

1. Jannini, EA et al. (2010) Who's Afraid of the G-spot? Journal of Sexual Medicine. 7:25-34.
2. Burri, AV et al. (2010) Genetic and Environmental Influences on self-reported G-Spots in Women: A Twin Study. Journal of Sexual Medicine. 7:1842-1852.
3. Wimpissinger, F et al. (2007) The female prostate revisited: perineal ultrasound and biochemical studies of female ejaculate. Journal of Sexual Medicine. 4:1388-1393.

1 comment:

  1. I think your estimation is right on the money.  Many variables, but I think the overriding determination is the size, location and enlargement properties of the clitoris in conjunction with the thickness of the interior vaginal tissue.  The bigger and/or more sensitive the clitoris, the more likely she is to claim she has a G-spot.

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