Archive for "Human Sexuality"

The Secrets Behind Penis Shape and Vigorous Sex

Posted in Science with tags , , , , , , , on June 25, 2009 by neandergal

No, these secrets have nothing to do with the sexual prowess of the new found love of your life, but a human evolutionary process that gives rise (no pun intended) to the shape of the human penis today.

An article, Secrets of the Phallus: Why Is the Penis Shaped Like That? in Scientific American by Jesse Berring gives us an explanation of why the shape of the penis is the way it is today and how its anatomy plays a role in reproductive success by displacing sperm in the vagina placed there by other mates. The process is known as the “Semen Displacement Theory.”

The “head”, otherwise known as the glans penis acts as a plunger that sucks out semen possibly placed by a competitor. Those mates equipped with a better “plunger” stood a better chance of displacing another male’s semen and therefore more chance of passing on their genes. The article refers to a behavioral study that shows how sex is more vigorous if a mate suspects infidelity. More vigorous and deeper penetration also means more semen displacement.

Another revelation is how the post ejaculatory sleepy affect acts as prevention against the possibility of “self-displacement of semen” by a second helping of subsequent sex. The refractory period plays a part in reproductive success by acting as a mechanism for avoiding self displacement of semen and gives sperm time to reach an ovum. If you are too tired and temporarily impotent to engage in a second helping soon afterwards, there is less chance of displacing semen and therefore more chance of impregnation.

In other words, the evolutionary process is most definitely involved in the shape of things to come, in a manner of speaking.

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The Science Behind Female Ejaculation

Posted in Science with tags , , , , , , , , , on May 28, 2009 by neandergal

Proper discussion and research on female sexuality and in particular, female ejaculation has been a long time coming. Female ejaculation is often dismissed as myth and mainly attributed to loss of bladder control at the time of orgasm. This is of course still true for some cases, but not all.

Laboratory analysis of fluid expelled from a small group of females who claim to experience female ejaculation tells a different story. A recent report, Everything you always wanted to know about female ejaculation (but were afraid to ask) in New Scientist describes how researchers found significant quantities of the protein prostate-specific antigen (PSA) present in in the fluid. Prostate cells in the male prostate gland produce PSA which is present in serum and semen.

Ultrasounds of the women who experienced female ejaculation showed evidence of a structure surrounding the urethra that is similar to the male prostate gland. The area of the female prostate is located near the G-Spot and is most sensitive to sexual arousal. It appears that stimulating the G-Spot also stimulates the female prostate resulting in ejaculation.