On the Science of Changing Sex

A Show of Hands

Posted in Science Criticism by Kay Brown on January 15, 2015

A recent paper seemed to be lending weight to the hypothesis that prenatal androgen exposure dose may influence transsexuality.  The papers concern the use of 2D:4D finger length ratio as a proxy measurement of prenatal androgen dose exposure.  I’ve written about this before, but please allow me to cover the basics again.

handThe 2D:4D ratio is mildly sexually dimorphic based on the androgen/estrogen ratio during fetal development.  The conventionally approved method of measuring the 2D:4D ratio is from the middle of the crease between the finger and the palm to the middle of the tip of the finger.  When I measure mine, I find that for the left hand, they measure 67mm:62mm giving a 2D:4D ratio of 1.08.  For my right hand, I measure 67mm:63mm, giving a 2D:4D ratio of 1.06.  If you are wondering, this is an extremely feminine (hypomasculine) 2D:4D ratio, which would be very unusual to find in a western european male (mostly Irish descent).

finger vs sexWhen we do this measurement for a large population and graph it as a histogram, as shown on the right, we see that the average male hand has a 2D:4D ratio of 0.975, and the average female hand has a 2D:4D ratio  of 0.995.  One also notices that there is a range, a classic bell curve, of ratios.  Note that they are highly overlapping, but still recognizably separate (effect size d=0.63).  Thus, for any given individual, the ratio is essentially meaningless.  It is only when we look at large numbers, can we average out the noise, the random factors that push the measurement one direction or the other, that we can see a real signal that might give us interesting clues to scientific questions.  Different ethnic populations show different average and effect sizes, so it is important that when conducting a study of this type, that the controls be from the same ethnic population as the subjects.

2d4d SerbsIn the Vujovic paper, they compared a group of FtM and MTF transsexuals to controls, all of whom were ethnic Serbs.  The paper was very confusing in that in the text, they use the conventional 2D:4D ratio.  But the accompanying bar chart, shown on the left, appear to have flipped this for some, but not all, to use 4D:2D ratios !  This kind of error should have been spotted during peer review.  (I’ve seen exactly this kind of error in the papers that I’ve reviewed for journals… it is common to find mislabeling of figures, etc. due to multiple contributing authors.)  So, let’s ignore the bar graph and look at the numbers?

“Our study found larger 2D : 4D for right hand in control males, compared to left hand (0.928 versus 0.935). Control female exhibited, as well, larger 2D : 4D for right hand, compared to left hand (0.921 versus 0.945). Control males left hand ratio 2D : 4D is lower (0.935) than in female left hand control (0.945) while there were no differences for the right hand (0.928 versus 0.921).”

Oh dear… if you follow that text carefully, one realizes that once again, something is messed up.  The larger numbers were supposed to be for the right hands in the first two sentences, but now it appears, from the third sentence, that the opposite is true.  Once again, it appears that the ratios have been flipped from 2D:4D, to 4D:2D in the numbers in the text, but that the original writer of the words had intended to use the conventional 2D:4D ratio… but someone inserted the flipped numbers at some point.  (Again, this should have been caught at peer review!)

So what is going on?  Clearly this paper could NOT have been peer reviewed, since if it had, these simple and inexcusable errors would not have been allowed in the final version of the paper.  The answer is simple.  The journal in which this paper was published is NOT peer reviewed.  In fact, it is an egregious example of what many in the scientific community are calling “predatory publishing”, as Jeffrey Beall explains,

“An example of a gold open-access journal is The Scientific World Journal, currently published by Cairo-based Hindawi Publishing Corporation. This megajournal covers virtually all scientific fields and imposes an article processing charge of $1,000 for each accepted article. “

As Beall has pointed out, because this is not a peer reviewed journal, not even a subject focused journal, quite literally (not figuratively) anyone can publish ANYTHING in these journals, most especially this one, as long as you pay the publishing fee.  The process of academic science depends upon peer review to keep everyone honest, to keep junk science, non-science, erroneous and, most especially, fake data out of the publications.  This “journal” does none of that.

Thus, this paper is of questionable value to the scientific community… and especially to the trans-science-skeptic like me.  How can I trust the data presented?  How can anybody?  We can’t.  I don’t.

Addendum 1/16/2015:  In doing a bit more research into this journal, its publisher claims that it uses a single-blinded peer review process.  But, I’m still convinced that it could NOT have been properly reviewed.  It took me only a few minutes to realize that the graphs, text, and numerical values were messed up.  One would NOT need to be a specialist to see the error, merely scientifically literate.

Addendum 2/17/2015:  I wrote to the lead author of this study asking for the correct data.  She didn’t bother to read my letter, nor this blog post, with any depth, because her response was non-nonsensical, starting with misgendering me, likely not understanding that the name “Kay” in English denotes a woman’s name, not a man’s.  But in any case, it means that she hadn’t bothered to look at my blog post, nor my “about” page:

Mr. Brown,

Thank You for Your kind email.

Figure 1 was excluded from the paper because men created it made a mistake (incidentaly he took data from another study).

I am sorry for this mistake.  All other data in the text are correct.

We followed up transsexuals since 1989. and have many interesting data. So, if You have any interest we can have further successfull cooperation.

Best wishes,

Prof.Svetlana Vujovic


Vujovic et al., “Finger Length Ratios in Serbian Transsexuals”, The Scientific World Journal

Jeffrey Beall, “Predatory Publishing”, The Scientist Magazine, August 2012


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