The case of the female orgasm pdf download lloyd






















Or consider the matter of orgasm and reproductive success. There are no data showing that orgasm enhances reproductive success; but nor are there data showing that it doesn't. What conclusion can we draw? None: absence of evidence is not evidence of absence. Or consider the fact that not all women experience orgasm during sex. Lloyd equates variation in phenotype with proof that natural selection has not acted. But this need not be so: we all have eyes, yet we cannot all see equally well.

No one would argue that eyes have not evolved under natural selection on vision. The sad fact is that, for now, all statements about the evolution of the female orgasm are conjectures in an empirical vacuum. To advance the debate, we need data. The most obvious approach would be to ascertain whether there is or was a link between orgasm and reproductive success.

Measuring the relationship between a given trait and reproductive success is difficult in any organism. It is obviously impossible to know whether orgasmic women have tended to have more children than anorgasmic women.

The best we can do is try to infer. The fact that orgasm is not necessary for conception rules out the obvious way that orgasm could enhance reproductive success — but it could have more subtle effects. For example, could orgasm during sex induce ovulation? In mammals such as ferrets and cats, ovulation is induced by stimulation from the male; might it be facultatively induced in humans? As far as I know, such an effect has not been reported for any primate, but then, as far as I know, no one has looked for it.

We also need to know far more about the nature of orgasm. Orgasm is the result of two phenomena: contractions in the pelvic region, and the perception of pleasurable sensations by the brain. Yet we have little understanding of how the two components relate to each other. Moreover, a distinction is often made between clitoral and vaginal orgasm.

Whether these are physiologically different — let alone whether they evolved under different selection pressures — is unknown. Indeed, the neuroanatomy of the genital region is poorly understood, and we have scant data on how much it varies among women.

Brain scans suggest that different parts of the brain may be involved in orgasm for males and females — which would be consistent with natural selection acting on females directly — but the sample sizes are as yet too small to draw confident conclusions. To understand the significance of the variation in women's experience of orgasm, we need to know what causes this variation. Is it due to genetic differences in genital anatomy? To differences in the way brains perceive pleasure?

To psychological or cultural factors? Or to a physical incompatibility between a woman and her partner s? In other words, do some women lack a capacity for orgasm, or is the capacity there but never realized? Again, data are lacking. A recent twin study K. Dunn et al. And we need to know more about when other primates experience orgasm. Do females in other species have orgasms with some males but not with others? No one knows. Here, too, we need to know how pelvic contractions translate into brain waves.

And we need to investigate males as well as females: it is often simply assumed that males in other species have orgasms. Data on other primates will help us to understand the relationship between male and female orgasm, and whether the female orgasm evolved before the split between humans, chimpanzees and bonobos.

In short, it's time to collect data. Without it, the debate will remain like sex sometimes is: furious, empty and anticlimactic. You can also search for this author in PubMed Google Scholar. Reprints and Permissions. Judson, O. Nature , — Download citation. Alexander, R. Chagnon and W. Google Scholar. Arnqvist, G. Sexual Conflict New Jersey: Princeton, Baker, R. Article Google Scholar. Barash, D.

Benshoof, L. Borrello, M. Brown, G. Buller, D. Campbell, A. Caton, H. Connell, K. Daniels, D. Dawood, K. Dixson, A. Dunn, K. Ericksen, J. Flinn, M. Hrdy, S. Bellig and G. Judson, O. Kinsey, A. Saunders and Co. Levin, R. Lloyd, E. Lovejoy, C. Mayr, E. Morris, D. Pawlowski, B. Petrie, M.



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