In Wikipedia's article of Orgasm it suggests vaginal stimulation isn't sufficient for women's sexual pleasure:
Kinsey found that most of the women he surveyed could not have vaginal orgasms.[59] He "criticized Freud and other theorists for projecting male constructs of sexuality onto women" and "viewed the clitoris as the main center of sexual response" and the vagina as "relatively unimportant" for sexual satisfaction, relaying that "few women inserted fingers or objects into their vaginas when they masturbated". He "concluded that satisfaction from penile penetration [is] mainly psychological or perhaps the result of referred sensation".
Is it true that most women cannot have vaginal orgasms (i.e. orgasm from vaginal stimulation alone)?