August 9, 2012
to be posted on

Nathaniel Comfort
Associate Professor
History of Medicine
Johns Hopkins University
1900 E. Monument St.
Baltimore, MD 21205
twitter: @nccomfort

Dear Professor:

I had written you before about Rh incompatibility, and you were kind enough to steer me to the work of William Allen.  My thanks again on that.  Sadly the dear friend I had who was the only woman I know of directly who nearly died of giving birth to too many babies with Rh incompatibility has herself lost her heroic battle with a disease.  I miss her dreadfully.  And she was the only one who had taken an active interest in the Rh problem as well as with the larger problem of diverse gene pool: it destroys fertility. 

I am delighted to see your recent article (Nathaniel Comfort, Under the skin NATURE vol. 513 no. 7518 September 18, 2014 page 306).  As a doctor I say you hit the nail square on the head.  When I was in training we were expected to begin the presentation of the patient with the words; The patient is a (age) year old (race) (sex) who…).  I always found the requirement to include race as pointless.  Why?  Was I supposed to achieve “racial balance” in my diagnoses?  That made about as much sense as racial balance in schools.  My job was to listen to my patient’s complaint and to try to put medical science to work to help.  If the patient had XYZ diagnosis, that was what I needed to understand.  The business of education is to give instruction that will benefit the student.  Duh.  When we placed social values above didactic ones we took the best public education system in the world (unfair to say of course, as other countries were either tiny, poor or recently shattered by war) and trashed it.  Segregation was wrong.  So was integration, at least from a medical standpoint.  Once I was in the middle of writing up an examination and realized I couldn’t remember the race.  I had to go back to the patient and take a look.

You boldly address the question of whether “race” is real.  I call it irrelevant, and perhaps alone I have numbers to prove it, which I shall get to in a bit.

But race is very real from a psychological standpoint.  A number of studies have shown that even people who deny racial prejudice can be caught out with a psychological test.  Those who pass may be caught by a more subtle test, and those that pass that one by one more subtle still.  In the end one comes to believe that everybody has it, and the only ones who pass are those who are smarter than the designer of the test. 

There is another psychological phenomenon called the “uncanny valley.”  If something looks right, all is well and good.  If it looks wrong, it’s just different.  But if it looks almost but not quite right, then it’s disturbing.  My sense is that on average I get along with people of other “races” rather better than with my own and get along with my own Scotch Irish group worst of all.  But my kin, even distant cousin, ah then I warm right up.  That is not any moral superiority on my part.  I am just more sensitive than most, and my uncanny valley is a little closer in.  For most of the world it probably lies smack across race or tribe or whatever. 

So why should we be drawn to kin and disturbed by outsiders, even those who are almost but not quite kin?  It’s natural selection at work.  If you marry kin, and I mean out to sixth or seventh cousin, you will have ample fertility, at least if your line has been doing so far many generations.  Marry outside and you will pay a fertility penalty.  The rich world is so outbred that our infertility has accumulated to the point where we no longer replace ourselves.  If nothing changes, and quite likely no matter what changes, we shall go extinct.  There is evidence for this at

So here is my promised reply to those who would say, “Europeans have become the world’s richest and most powerful people mainly because genetically the most open, curious, innovative and hard-working.”  So let’s look at all of history in a single geographic area, lower Mesopotamia, the place that has the longest unbroken historical record.  Among the regimes that have ruled there are Europeans, under Alexander, and Aryans, so beloved of certain race theorists.  We take the number of years that each regime lasted and line them up with the shortest lasting at the beginning and the longest lasting at the end.  Then we break them up into 50 year intervals and count the number in each interval.  Then we ask, “Of those that lasted fifty years, how many made it to 100, and of those that lasted 100, how many lasted to 150 and so forth.  Then we graph age in fifty year increments against chance of survival. 

Before looking at it, think what you expect.  If climate change, comet impact, volcanism or other things that arise outside the population are the things that bring down societies, the line will be noisy but horizontal.  If genetic advantage, political correctness, right religion or anything else that is a characteristic within the population is effective, the line should be noisy but go up because of the effect of selection.  So I attach the graph.

The line is very clean, so there is only one cause, and it is neither in the population nor outside it.  It can only be the very fact of a large, socially united population.  Have a look.

So no, there is no such thing as genetic advantage.  We are all in the same boat.  Marry kin or die.  Racial prejudice does almost nothing to encourage us to marry kin.  It is not adaptive.  It is merely the extreme of a very adaptive love of cousins.

That love appears to have been lost in our society.  I find that troubling, and it leads me down pathways I’d rather not go into just now.  I did think you might be interested in the evidence.

Thank you for a thoughtful paper as well as for past kindnesses.

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