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Unformatted text preview: big around and as long as an erect penis, into the vaginas of sexually
aroused women, and from ten firsthand insights he drew what he
imagined would be the position of the genitals during a natural act of
sexual intercourse. There are no obvious errors, no serious deviation
from what we now consider to be true human anatomy. Shown in
cross-section, the penis extends deeply and very nearly straight into
the vagina. That, it turns out, is wrong. But working with glass tubes
and only half the partnership, Dickinson could hardly have done better. That was nowhere near the end of this investigation.
Thirty or so years after Dickinson peered through his tubes, William Masters and Virginia Johnson took another shot at it. They used
a mechanical penis that could artificially simulate coitus and direct
observation using a speculum and “bimanual palpation,” or manual
examination of the internal organs from both inside and outside the
body.13 Their most notable findings included the observation that, during intercourse, the uterus enlarged and the vaginal walls shifted, things
not seen by any earlier observer.
Unconvinced by Masters and Johnson’s findings, British physician
A. J. Riley and his wife used ultrasound technology in 1992 to further
investigate the anatomy of coitus.14 Unfortunately, the pictures they
produced were of very poor quality—largely because they used inexpensive equipment and carried out all their scans on themselves while
having intercourse—and their studies provided little in the way of further useful information.
The most recent of these sorts of studies took place in 1999, in
Groningen, the Netherlands, when gynecologist Willibrord Weijmar
Schulz, physiologist Pek van Andel, anthropologist Ida Sabelis, and
radiologist Eduard Mooyaart used magnetic resonance imaging (MRI)
to attempt to definitively and finally reveal the secrets of human mating. They found that “during intercourse in the ‘missionary position’ the
penis has the shape of a boomerang, and 1/3 of its length consists of
the root of the penis. During female sexual arousal with intercourse the
uterus was raised and the anterior vaginal wall lengthened. The size of
the uterus did not change during intercourse . . .” even though Masters
and Johnson swore it did. Schultz and his colleagues don’t say how they A Brief History of Sex 23 got those couples into an MRI tube, how they managed to get any clear
images at all, or whether all of that may have affected the relative locations of any the important parts. But for the moment it seems to be the
definitive study.15 However, we’ve already seen the sorts of problems
that arise when something gets labeled “the definitive study.”
Interestingly, in none of these studies did the authors think to question whether their findings and conclusions would be meaningful for
more than the one man and one woman who had participated in the
particular study. No one ever asked whether the obvious differences in
genitalia among men and among women might have some relevance,
or considered that the anatomy of intercourse might be as varied as
the men and women engaging in it. Just as we have come to think of
biological sex as offering only two opposite options, we have come to
imagine that sex between any man and woman is just like sex between
every other man and woman.
You’d think that after all these years, after all the drawings and pictures, the ultrasounds and MRIs, we would have it right by now. Yet the
sexual anatomy of human beings remains an evolving and sometimes
Changing Times, Changing Sexes: Science as a Moveable Feast
Or rather, sexual anatomy and the differences between men and women
were evolving concepts, right? Now we have it correct, and the story has
stopped evolving. Today we have a place for everything, and everything
is in its place. The curlicue of the clitoris nestles in its proper crown. The
ball bearing of the testicle lies oiled and sheathed beneath the caliper of
the epididymis. All is right and fixed in the anatomical world, isn’t it?
Perhaps not. For example, nested just above human and most other
mammals’ hearts is an organ called the thymus. In immunology there
is no organ as singularly important as the thymus; within its membranous walls, our immune systems learn the mystery of self/non-self
discrimination. Without thymuses, humans and other animals disintegrate under the onslaught of infection. If you transplant skin from,
say, a normal chicken onto a normal mouse, within just a few days the 24 Between XX and XY mouse will mount a violent immunological attack on the chicken skin
and reject it. If you perform the same experiment using normal chicken
skin and a mouse without a thymus, the mouse will grow feathers. Mice
without thymuses have lost the ability to distinguish themselves from
chickens. That is a very serious sort of identity crisis.
Obviously something nearly miraculous happens inside of mammalian thymuses. This organ’s role is so crucial to the developing immune
system that f...
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This document was uploaded on 02/04/2014.
- Spring '14