Science still needs to justify pleasure

Why do women orgasm? Scientists shed light on the evolutionary mystery, by Carmen Chai

A Canadian study examining the sex lives of Americans says having more sex doesn’t necessarily lead to a happier relationship. Rosey Edeh has the story.

We know why men do it, but why do women orgasm? While most human functions have a purpose, scientists have been stumped as to why women orgasm — until now.

New research out of Yale University suggests that, from an evolutionary standpoint, women used to climax to prime their bodies for ovulation. Orgasms would flood women’s bodies with hormones and muscle contractions that readied them for producing an egg and baby-making.

This must have been the mechanism for female orgasms about 150 million years ago, the scientists say.

But since then ovulation has changed, and the female orgasm has taken on other roles, such as helping with bonding, the doctors guess.

“It is important to stress that [orgasm] didn’t look like the human female orgasm looks like now. We think that [the hormonal surge] is the core that was maybe modified further in humans,” study co-author, Mihaela Pavlicev, told the Guardian in the U.K.

“There is a lot of discussion about whether [the female orgasm] could have any functions like in bonding behaviour and things like that — so we cannot exclude that it actually has co-opted some other function after it lost its function in reproduction,” Pavlicev said.

When men orgasm they ejaculate, a key step to procreating and passing on their genes. The reason why they orgasm are much more obvious, but the explanation behind the female orgasm hasn’t been as clear-cut.

Pavlicev says that female cats, rabbits, and camels — among other mammals — rely on hormonal surges during orgasm to tell their bodies to release an egg. These animals ovulate only after having sex.

Humans probably turned to orgasming for a “direct reproductive role,” too. But some mammals’ interaction changed: primates, for example, turned to social interaction and regular sex.

The scientists suggest that after that, some mammals, including humans, released eggs on a regular cycle instead of only after mating. They didn’t need to climax to ovulate.

Now, women have sex without orgasming at all, the researchers note.

“It seems very natural not to automatically accompany orgasm with copulation,” Pavlicev said.

Orgasm is key to partner bonding, experts say. After you climax, oxytocin, which is nicknamed the “cuddle hormone,” flows into your system.

It’s notorious for making you want to bond and have genuine intimacy with your partner beyond the physical.

Read Pavlicev’s full findings published in the journal JEZ-Molecular and Developmental Evolution.

Orgasms Are Like Nipples, They Are Functional In One Sex And Inherited In The Other by Justin S. Rhodes

An article was recently published in the Journal of Experimental Zoology claiming to have discovered a possible explanation for the evolutionary origin of the female orgasm. First, to quickly restate the problem: females do not need to orgasm to reproduce, and only approximately 1/3 of women orgasm during copulation. It is not as if the 2/3 of the rest of human females do not orgasm. Females have plenty of orgasms. But, the female orgasm usually involves clitoral stimulation, and unfortunately, the clitoris is just not in the right place for most sexual positions involving penile vaginal penetration. The clitoris is homologous to the penis (i.e., same genes and developmental pathways lead to both organs), so it is not surprising that clitoral stimulation leads to orgasm. The question then becomes: why does orgasm in females occur if it is not necessary for reproduction?

The authors of the Experimental Zoology article claim that the female orgasm originated in earlier species of animals in which ovulation required clitoral stimulation from the male. Their stated position is that the orgasm was subsequently retained (i.e., vestigial) along the evolutionary lineage that led to humans even though ovulation was no longer dependent on copulation. However, there is no evidence that stimulation-induced ovulation in earlier species resulted in orgasm. An orgasm is a perception of intense euphoria accompanied by gyrating muscle contractions.

The real question that should have been asked is why wouldn’t females have orgasms. If there was strong selection for orgasms in males, then females would have inherited the trait as long as it did not impair their survival or reproductive success. Males have nipples for the same reason. Nipples evolved for a specific function in females, and males also have nipples because they inherited the genes and programs to build nipples from females. As long as nipples do men no harm, there is no process in evolution to prevent males from having them, so they do.

The orgasm has a very important function in the reproductive success of males. Every time a fertile man has an orgasm during intercourse, he ejaculates and there is a chance for a fertilization event. The male orgasm occurs in nearly 100 percent of the copulation events. Further, from the standpoint of evolution, the euphoria part of the orgasm is a creative solution to the problem of how to make an animal behave in ways that maximize their reproductive success. If orgasm is associated with pleasure, then by definition males will try to seek it out and in the process will fertilize females. If the male orgasm is an adaptation for motivating reproduction in males, then that means natural selection has favored genes which orchestrate the development of nerves and hormonal responses necessary to achieve an orgasm in response to specific stimulation of the penis. These genes will be inherited by female offspring as well. Why wouldn’t they be?

Humans are biased in assuming the existence of a trait always must have a functional explanation. But that is not how evolution works. The female orgasm, like male nipples, are important examples to remind us that evolution produces sufficient not optimal solutions. Even though it may not make sense for females to have orgasms, because it serves no function for them or their ancestors, it still may occur as a side effect of selection on some other trait, in this case male orgasm. The mystery of the female orgasm has been thoroughly investigated already by Dr. Elisabeth Lloyd in her book, The Case of the Female Orgasm- Bias in the Science of Evolution. Bottom line, all that is necessary to understand the origin of the female orgasm is to understand the origin of the male orgasm, and that is easy, it serves a crucial function in motivating intercourse.