This amazing painting is by Zeynep Beler. Visit some of his work here!

This amazing painting is by Zeynep Beler. Visit some of his work here!

Evolution of the Female Orgasm

The science of the human female orgasm is a fascinating area of controversy, confusion, and of course, mystery. Believe it or not, some scientists still debate the existence of the G-spot! Maybe they should get out the laboratory and do some naturalistic research...

Anyway, I study humans from an evolutionary perspective, meaning that I ask questions concerning the origin of and variation in traits and behaviours within our species. Taking an evolutionary approach to understanding humans and our behaviour provides unique ways of understanding and answering research questions. In contrast to asking questions about how a certain trait works, evolutionary scientists think in terms of the big picture: why does a certain trait exist in the first place? 

In evolutionary science, we tend to ask why, while other sciences- such as medical science- we tend to ask how. 

Let's use an example to illustrate what I mean:

Lauren is diagnosed with schizophrenia.  Here are some examples of research questions that different kinds of scientists might ask:

  • Is there a connection between Lauren's history of childhood trauma and her onset of schizophrenia?
  • How do the levels of dopamine in Lauren's brain affect her schizophrenic symptoms?
  • Which combination of schizophrenia risk alleles (variants of genes) run in Lauren's family?

Some possible answers might be:

  • Lauren's childhood trauma shows up in the content of her schizophrenic delusions.
  • Lauren has schizophrenia because the levels of dopamine are erratic relative to someone without schizophrenia.
  • Lauren had a genetic predisposition to schizophrenia which was triggered by maternal sickness during pregnancy.

All of these questions are useful and all of the answers are at least somewhat true. An evolutionary question is different:

  • Why are humans, as a species, at risk for developing schizophrenia? 
  • Why does schizophrenia persist in humans even though it's clearly maladaptive?

Some possible answers might be:

  • Human-specific functions such as language and creativity create increased risk for break down, which looks like schizophrenia.
  • Some elements of schizophrenia or mild schizophrenia may give some advantages to some people in some environments.

So, I'm interested in the question:

Why do human females orgasm?

In males, the function of orgasm is simple (or at least appears to be simple): ejaculation of sperm is necessary to impregnate a female (most of the time) and therefore the orgasm reflex is highly adaptive.  Virtually all men are capable of orgasm and ejaculation. 

In females, the orgasm is much more confusing. Some females orgasm, some do not, there are multiple kinds of orgasm and huge variation in orgasm triggers, and orgasm does not appear to correlate with fertility or number of children. So, why do females orgasm? What is the function or is there even a function of orgasm in human women?

Some researchers believe that female orgasm is simply a really great adaptive byproduct. Male and female fetuses share many features of embryological development and because selection was so strong for the orgasmic reflex in males, females end up with erectile tissue and the orgasmic reflex as well (this is the reason why males have nipples - they are non-functional but necessary in females so because of our shared development in the uterus, BAM, males get nipples too!).

Other researchers believe that females orgasm as a way of testing and choosing high-quality mates. Evidence for the mate-choice hypotheses is not  strong. 

The main problem with posing a functional answer to the question of why females cum is difficult because orgasm rates in women are unfortunately pretty low. If orgasm had some super important function, all women would need to orgasm like men do!

I think I've come up with a pretty good hypothesis to this conundrum. I can't tell you what it is yet until I get my ideas and research together a little more. It's a big process to do all the background research, develop the hypothesis, find existing support in the literature, formulate ways to test the hypothesis, and of course, write it all up to share it with you and the broader scientific community!