Are women “designed” for rear entry?

One of the odd things about human female anatomy is the way in which the vagina is quite posterior and close to the anus. This has led to much commentary, ribald and otherwise.


In fact, as the above saggital view of the female pelvis shows, the vagina is more or less halfway between the front and back of a woman’s body. As I once heard it remarked, the vagina is “further back than most people realise”.

The human evolutionary move to an upright stance has traditionally been understood to have resulted in a general move anteriorly of human primary and secondary sex organs and sexual behaviour, so that female breasts make a prominent display high on the chest, and sexual intercourse occurs face-to-face. However sex from the rear remains part of the human behavioural repertoire and excites lively popular interest. The frequency of the use of this position in the imaginary world of Westeros in the TV series Game of Thrones has been commented upon.

Lordosis, the reflex in sexually receptive female mammals involving presentation of the rear for intercourse is not generally considered to be part of the human female sexual response, although this source nevertheless refers to a suggestion that “when a human female wears high-heeled footwear, the buttocks thrust out and the back arches into a pose that simulates lordosis behavior, which is why high heels are considered “sexy”.” That is one theory, and I have written about the appeal of high heels here. A commenter here mentions “lordosis” as a possible factor. In that discussion, I tend to discount rear entry as a normal part of the modern human repertoire, although now I am less sure.

There is some more discussion of the resemblance of the receptive behaviour of humans during rear entry to “lordosis” here.

In any case, I have speculated here that “the vagina has remained somewhat posterior in humans to allow rear-entry intercourse as an option although rear entry is not very common ethnographically … the closeness of the vagina and anus in women may be due to the evolution of both front and rear entry as options in human intercourse.”


7 responses to this post.

  1. Then, of course, we come to the birthing process. Once, it was thought, a hatch in the front of the belly area should have been evolved. It may well have made bringing forth life a little easier, although the door-knob might have proven an uncomfortable impediment. But as it was to eventuate the sperm input channel doubled as a baby output channel and that, in a biped, is more convenient simply ‘straight down’.


  2. Posted by Julian O'Dea on June 6, 2015 at 5:11 pm

    An alternative possibility is that rear entry intercourse is what Stephen Jay Gould called a “spandrel“, something that was not selected for evolutionarily but is incidentally possible.

    Anal sex might also be a spandrel in that sense.


  3. Posted by Julian O'Dea on May 12, 2016 at 1:57 pm

    “Both the novels and TV series also note that the Dothraki prefer rear entry/”doggystyle” sex positions between men and women, i.e. in the novels Daenerys’s narration at her wedding notes that the Dothraki men are having sex with the women from behind in Dothraki fashion.”


  4. Posted by Julian O'Dea on May 25, 2016 at 2:28 am

    Strippers seem to alternately present their genitals from the front or rear in this situation:


  5. Evolution doesn’t tend to cause changes that aren’t needed. Rear entry would have been how sex happened when on all fours and since the position didn’t hinder either sex or childbirth once standing upright, there was no reason to change it. Making sex from either approach an enjoyable option.


  6. Posted by Zeta on June 27, 2016 at 10:26 am

    A blond, brunette and red head were talking. The brunette said she was pregnant and that she was going to have a boy because her husband was on top. The read head said she was pregnant and going to have a girl because she was on top. Then the blond started crying and the other two asked what was wrong? The blond said “were are going to have puppies.” (-:


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