The existence of the G-spot has not been proven, nor has the source of female ejaculation. Although the G-spot has been studied since the 1940s, disagreement persists over its existence as a distinct structure, definition and location. The G-spot may be an extension of the clitoris, which together may be the cause of orgasms experienced vaginally. Sexologists and other researchers are concerned that women may consider themselves to be dysfunctional if they do not experience G-spot stimulation, and emphasize that not experiencing it is normal.