What is the purpose of the ever-elusive female orgasm?
In males, orgasm is invariably required for ejaculation and transfer of sperm, researchers noted in a piece published recently in the Journal of Experimental Zoology. "But in females its function is unclear," wrote Mihaela Pavlicev, a researcher at Cincinnati Children's Hospital Medical Center, and Gunter Wagner, a professor of ecology and evolutionary biology at Yale University.
In women, the orgasm does not contribute to reproductive success and accompanies intercourse only "unreliably," they said. So, what gives?
The researchers examined many species of mammals and proposed that orgasm in women evolved from an ancient trait that once played a key role in reproduction.
To discover the big O's reason for being, the researchers explored its underlying physiology and focused on the hormonal surge that women experience while in the throes of passion. Keeping this foremost in mind, Pavlicev and Wagner then looked at other mammals. Despite the enormous diversity of reproductive styles, they were able to identify core characteristics of reproduction and track how these features evolved.
The evolution of ovulation
Certain species of mammals are reflex ovulators. For example, female cats produce a mature egg ready to be fertilized by sperm only when stimulated by intercourse with a male. By comparison, women are spontaneous ovulators who produce eggs monthly, independent of sexual intercourse.
Looking at the distribution of these two types of ovulation across all the species of mammals, Pavlicev and Wagner inferred that male-induced ovulation must have evolved first and spontaneous ovulation later.
If female orgasm, by causing a hormonal surge, helped induce ovulation, this means it once played a direct role in reproduction. Over time, though, spontaneous ovulation evolved, rendering the female orgasm unnecessary.
Looking at the evolution of female genitals, the researchers found additional evidence that orgasm once played a fundamental role in reproduction. As females moved away from reflex ovulation toward spontaneous ovulation, the clitoris -- the major source of orgasm -- moved away from the location of sexual intercourse, the vagina.
All this adds up to broader implications for women, Pavlicev and Wagner suggested: The low frequency of female orgasm -- only a quarter of all women reliably achieve orgasm during intercourse -- is not an individual woman's failing or a physical impossibility but a natural consequence of evolution.
Others challenged this theory.
More here: http://edition.cnn.com/2016/08/02/health/female-orgasm-evolution/index.html
In males, orgasm is invariably required for ejaculation and transfer of sperm, researchers noted in a piece published recently in the Journal of Experimental Zoology. "But in females its function is unclear," wrote Mihaela Pavlicev, a researcher at Cincinnati Children's Hospital Medical Center, and Gunter Wagner, a professor of ecology and evolutionary biology at Yale University.
In women, the orgasm does not contribute to reproductive success and accompanies intercourse only "unreliably," they said. So, what gives?
The researchers examined many species of mammals and proposed that orgasm in women evolved from an ancient trait that once played a key role in reproduction.
To discover the big O's reason for being, the researchers explored its underlying physiology and focused on the hormonal surge that women experience while in the throes of passion. Keeping this foremost in mind, Pavlicev and Wagner then looked at other mammals. Despite the enormous diversity of reproductive styles, they were able to identify core characteristics of reproduction and track how these features evolved.
The evolution of ovulation
Certain species of mammals are reflex ovulators. For example, female cats produce a mature egg ready to be fertilized by sperm only when stimulated by intercourse with a male. By comparison, women are spontaneous ovulators who produce eggs monthly, independent of sexual intercourse.
Looking at the distribution of these two types of ovulation across all the species of mammals, Pavlicev and Wagner inferred that male-induced ovulation must have evolved first and spontaneous ovulation later.
If female orgasm, by causing a hormonal surge, helped induce ovulation, this means it once played a direct role in reproduction. Over time, though, spontaneous ovulation evolved, rendering the female orgasm unnecessary.
Looking at the evolution of female genitals, the researchers found additional evidence that orgasm once played a fundamental role in reproduction. As females moved away from reflex ovulation toward spontaneous ovulation, the clitoris -- the major source of orgasm -- moved away from the location of sexual intercourse, the vagina.
All this adds up to broader implications for women, Pavlicev and Wagner suggested: The low frequency of female orgasm -- only a quarter of all women reliably achieve orgasm during intercourse -- is not an individual woman's failing or a physical impossibility but a natural consequence of evolution.
Others challenged this theory.
More here: http://edition.cnn.com/2016/08/02/health/female-orgasm-evolution/index.html
