In addition to vaginal sensitivity, some women reported that they had orgasm from vaginal stimulation. Masters and Johnson and Kaplan reported that there is only one reflex pathway in sexual response. In women, the clitoris is reported to be the major source of sensory input, the pudendal nerve is its sensory pathway, and the "orgasmic platform" undergoes myotonic buildup and discharge during orgasm.

Perry and I described a second reflex pathway that included the Grafenberg spot as the major source of stimulation, the pelvic nerve and the hypogastric plexus as its major pathway and the musculature of the uterus, the bladder, the urethra, the contractile elements associated with the paraurethral glands, and the proximal portion of the pubococcygeus muscle as its major myotonic responder. We claimed that this double-reflex concept could account for the reported ability of some women to selectively experience "vulva," "uterine" or "blended" orgasm, as described by Singer. (published in the G Spot, 1982)

I became interested in the phenomenon of female ejaculation, because I was teaching women to do Kegel exercises using biofeedback for stress urinary incontinence. However, we found that some of our subjects were women who only lost fluid at orgasm and these women seemed to have very strong pubococcygeus muscles. So we designed a study to determine if there was a significant difference in the muscle strength of women who claimed to ejaculate.

We developed a device to measure uterine muscle strength in addition to PC muscle strength, because of our hypothesis that there are two nerves involved in sexual response.

The phenomenon of female ejaculation refers to expulsions of fluid from the urethra. Many women reported having surgery to correct this "problem" and others reported that they stopped having orgasm to prevent "wetting the bed." The fluid was described as looking like watered down skim milk, tasting sweet and usually about a teaspoon in volume.

Six studies have been published in which the fluid expelled from the urethra has been subjected to chemical analysis. In four of these studies, the ejaculated fluid was chemically significantly different from urine, while in two studies, no significant difference was observed. Others have reported an expulsion of fluid with and without chemical analysis. The data reported in this slide show a significant difference between urine and female ejaculate in terms of prostatic acid phosphatase, urea and creatinine.