December 11, 2010

William Jefferson Clinton
c/o William J. Clinton Foundation
55 West 125th Street
New York, NY 10027

Dear President Clinton,
I was privileged to hear your address at the RSNA.  You mentioned having an interest in Haiti.  If you ever need a diagnostic radiologist to do some volunteer work I shall probably be available.

You also mentioned that it is possible for a population to have too many babies and for it to have too few.

As far as reducing the number of babies, there are effective means and I have nothing new to offer.  But as far as increasing the number, and there are countries where that is being tried, there is science that points the way but is known by very few people in spite of being published in the highly regarded journal SCIENCE.  These are what I think to be the key references.

  1. On the Regulation of Populations of Mammals, Birds, Fish, and Insects, Richard M. Sibly et al. SCIENCE vol. 309 no. 5734  JULY 22, 2005 page 607 – 610
  2. An Association between Kinship and Fertility of Human Couples Agnar Helgason et al. SCIENCE vol. 329 no. 5864 February 8, 2008 page 813 – 816
  3. Human Fertility Increases with Marital Radius, Rodrigo Labouriau et al. GENETICS vol. 178 no. 1 January 2008 page 601 – 603
  4. Comment on “An Association between Kinship and Fertility of Human Couples,” Rodrigo Labouriau et al. SCIENCE vol. 322 no. 5908 12 December 2008 page 1634 – 1635

Articles three and four go together. 

What these researchers all found was that normal fertility depends on mating with (in animals) or marrying (in humans) kin.  Of course this has been obvious for many years.  Everybody knows that farmers and people living in high valleys where the social pool is limited have big families, while people who live in cities, particularly prosperous people, have very small families.
Even with the numbers rigorously established and the role of choice proved to be very small indeed, actually invisible in the statistics cited, although I do think it plays a small part, even so people seem to have trouble believing the facts.  We have been told so often that genetic diversity is a good thing that we have come to believe it.

By the way, this effect develops so quickly that I do not believe it can be due to classical genes.  DNA is far too stable to account for the fertility decline.

I have a lot more data, but I shall not burden you with it.  The case is made three times in the literature referenced above. 

So if you ever deal with somebody lamenting a low birth rate, send that person to me.  There is much more to be learned and any new perspective or interest would be very valuable.


M. Linton Herbert

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