"Infant feeding: the physiological basis" (WHO, 1990) deals
          in ch. 3 with health factors which may interfere with
          breast-feeding. The section concerning "lactation
          failure" contrasts women in traditional societies who,
          despite a host of nutritional and other disadvantages, do
          not generally fail to secrete milk, and women in
          industrialized countries, where the "phenomenon" most
          frequently occurs. After 500 or so words and limited
          references, the section concludes: "Based on limited
          clinical experience in industrialized countries, it appears
          that a maximum in the range of 1-5% of women experience
          lactation failure on purely physiological grounds." The sole
          reference here is to the only citation then (or since)
          available to us in Geneva, Neville MC and Neifert, MR, ed.
          Lactation. New York, Plenum Press, 1983, p. 303. A quick
          check of the original chapter, authored by Neifert, gives:
          "On the other hand, a false notion, current among
          breast-feeding enthusiasts, is 'every woman can nurse'.
          While this philosophy is useful in combating the
          professional tendency to wean at the slightest obstacle, it
          appears that 1 to 5% of women experience lactation failure
          on a physiologic basis." That's it and not a *single*
          reference to the literature. If we're talking about
          the same "statistic", it appears that the original has been
          truncated and hardened into an absolute figure. If repeating
          something often enough makes it true, then I guess that
          pesky 5% figure qualifies.

          Jim Akre, Nutrition, WHO, Geneva