Okay, color me amused. There was a time when the standard feminist response to new evidence demonstrating that the G spot doesn't exist---at least in the sense of being a real spot that has a specific sensitivity, like the clitoris---would have been to say, "Of course. The G spot was invented in response to feminist skepticism about the 'maturity' of the vaginal orgasm over the clitoral one, to justify men who didn't want to engage in stimulation outside of the pump and dump." Which is why I was amused to see Mary Elizabeth Williams at Broadsheet get ruffled about a new study, involving twins, that demonstrated that the genetic arguments for the existence of a G spot have produced nada. I will say that some of the statements from the researchers incline me to worry about their objectivity---they are very committed to the idea that the subjective experience that could all be in your head is not "real" somehow, and they have strong opinions on the injustice of G-spot pressure---but hey, I'm willing to believe that there's no G spot if that's what the research finally concludes, after multiple, rigorous studies of course.
Feminist willingness to entertain the reality of the G spot is definitely an innovation of the past couple of decades, and it's for good reasons. One reason is that a lot of women stimulate this part of their vaginas while masturbating, and also that many lesbian-identified women report G-spot orgasms. This would incline one to think that there's an explanation for reporting of this beyond just men wanting to believe and women needing/wanting to please men. But I think the overwhelming reason is that the desire to believe women when they report subjective experiences is ascendant, while willingness to believe that women might trick themselves into believing something because it's what men want to hear is descendant in feminist thought right now. Women say they have G spot orgasms, we believe women, end of story. I respect where this desire comes from. Being a woman, I'm well aware of how much your ability to perceive objective reality is dismissed under the rubric that bitches are crazy. Especially when it comes to biology, there's a long-standing, ongoing problem of women's experiences being dismissed as being "all in their head", particularly when you're talking about issues such as chronic pain. Dismissals of the G spot can and often do come from that urge to believe that women are especially stupid and out of touch and probably mental. (To be fair, many feminists still are skeptical of the G spot, because so many defenses of it come from those trying to guilt women about desiring clitoral stimulation.) The other reason many feminists have moved into the pro G spot camp is because the amount of work it takes to produce that kind of orgasm puts mere 20 minutes bouts of cunnilingus to shame, and so you can't really say devotees of it are doing so because it appeals to male laziness.
But what this struggle ends up doing is obscuring that there's a third possibility, one that neither G spot defenders or dismissers seem willing to entertain, which is that the women's experiences can be totally real and also that there's no such thing as the G-spot. I mean, it's not like it's behind your ears or something; it's right by the clit, and inside the vagina, which is no slouch in the sensitivity department. Considering that some women can orgasm with very little stimulation or often just by willing themselves to come hands-free---and that both men and women are capable of orgasming in their sleep without masturbation---then it's certainly well within the range of possibility that women who get the specific G spot stimulation can have an orgasm without there actually being a specific G spot.
I suppose I see why this possibility (which I'm not married to or anything, just suggesting is a likely possibility) bothers people, and it's for the same reason that the placebo effect is unnerving. There's still a shame attached to the idea that something is "all in your head", as if that makes it less real. But if you think about it, it doesn't, because all experience happens subjectively. And by all, I mean all---the most extreme example is that you can't hurt a corpse by shooting it, but there are other ones as well. Pain feels very different depending on context, and it's been said that hangovers feel worse if you did something stupid while drunk. Our tendency is to want to say this experience is less real than that because our brains are constantly recalibrating how we feel something, but it's all equally real. If someone is more likely to have a G spot orgasm because she believes in the G spot, then that doesn't mean her orgasm was one teeny bit less real.
More power to 'em, I say. For those of us whose experiments with the G spot have resulted in skepticism and annoyance, there's a strong desire to believe that we're all being hoodwinked by the Sex Police that want all women to perform like porn stars, i.e. getting off in visually exciting ways that are completely penis-centered. (With "Deep Throat" winning an all-time award for wishing women had clitorises in their throats.) But intellectually, this desire is stifled by the amusement of watching someone make the "come here" motion inside a vagina until he's about to pass out from boredom while you're wondering if you're broken or something. It's interesting to consider if the G spot only occurs in some women, which would explain the huge gap between experiences without further shaming of women who don't have G spot orgasms. But what this research indicates is that if this is true, then it isn't genetic. I'm personally quite comfortable with the possibility that the G spot "exists" only in women that find the process of stimulating it exciting instead of boring, but of course, that kind of thing is culturally difficult to swallow.
The problem is that if the difference between having a G spot and not having one is suggestibility to the possibility---i.e. that you have orgasms by stimulating a specific part of your body when other women don't, because you believe that you can---then the shame would transfer from those who don't to those who do, who would be falsely led to believe that it's all in their heads and they're crazy or something. This is due to the aforementioned weirdness people have about believing that what's in your head is real, plus an giant dose of sexism. It's really too bad, because I think people are coming around to accepting that what is in someone's head is extremely important to the final result of orgasm, and that this can vary wildly. If this dude is excited by lingerie, but that dude prefers plain nudity, no one would claim that one of them had an orgasm that wasn't "real". But then again, they're both dudes, so that's the problem. When it comes to women, we want the body below the neck to be everything; the possibility that what's in your head is the most important thing of all is unnerving. Part of it is that society isn't quite up to the task of taking women's brains as seriously as they do men's brains. But part of it is that "it's all in your head" is used to dismiss the reality of women's experiences, even though something that happens in your head is quite real.
Maybe one day someone will conduct a responsible, objective, controlled study and get to the bottom of this. Ironically, this might actually go a long way to getting around the "damned if you do/damned if you don't" dilemma that creates all this angst, because the odds are very high that a responsible, well-researched theory will end up validating both those with and those withouts' real experiences.