Some are firm believers
The elusive erogenous zone said to exist in some women may be a myth, say researchers who have hunted for it.
Their study in the Journal of Sexual Medicine is the biggest yet, involving 1,800 women, and it found no proof.
The King's College London team believe the G-spot may be a figment of women's imagination, encouraged by magazines and sex therapists.
But sexologist Beverley Whipple, who helped popularise the G-spot idea, said the work was "flawed".
She said the researchers had discounted the experiences of lesbian or bisexual women and failed to consider the effects of having different sexual partners with different love-making techniques.
The women in the study, who were all pairs of identical and non-identical twins, were asked whether they had a G-spot.
If one did exist, it would be expected that both identical twins, who have the same genes, would report having one.
But this pattern did not emerge and the identical twins were no more likely to share a G-spot than non-identical twins who share only half of their genes.
Co-author of the study Professor Tim Spector said: "Women may argue that having a G-spot is due to diet or exercise, but in fact it is virtually impossible to find real traits.
"This is by far the biggest study ever carried out and shows fairly conclusively that the idea of a G-spot is subjective."
Colleague Andrea Burri was concerned that women who feared they lacked a G-spot might feel inadequate, which she says is unnecessary.
"It is rather irresponsible to claim the existence of an entity that has never been proven and pressurise women and men too."
Dr Petra Boynton, a sexual psychologist at University College London, said: "It's fine to go looking for the G-spot but do not worry if you don't find it.
"It should not be the only focus. Everyone is different."
The Gräfenberg Spot, or G-Spot, was named in honour of the German gynaecologist Ernst Gräfenberg who described it over 50 years ago. It is said to sit in the front wall of the vagina some 2-5cm up.
Recently Italian scientists claimed they could locate the G-spot using ultrasound scans.
They said they had found an area of thicker tissue among the women reporting orgasms.
But specialists warned there could be other reasons for this difference.