Karen Lindberg writes that Kathryn Dewey said:

> The
>standard infant weight gain charts were developed from the Fels Longitudinal
>Study which followed 867 babies from birth to 2 years in the town of Yellow
>Springs, Ohio.  Participants were primarily Caucasian, middle class and
>bottlefed.  Measurements were only taken every 3 months.

The Fels longitudinal study was only one of the sources for the growth data
that became the National Center for Health Statistics/World Health
Organization (NCHS/WHO) standards [also known as the pink and blue Ross Labs
charts].  The data from the NHANES study was used as well (National Health
and Nutrition Examination Survey) and new standards were generated and
published in 1979.  The NHANES data included about 10,000 children, measured
once, and included more variety in terms of geographic distribution (across
the US), ethnic variation (though not a lot), and feeding method (some
breastfed, some bottle-fed, some mixed fed).  Other factors complicating the
issue are that some of these kids started on cereals as early as 3 weeks of
age, and some of the Fels data includes kids from many decades ago who were
drinking various types of homemade formulas (cows milk, water, Karo syrup,
etc.).  So it's kind of hard to say what the standards really represent.  An
important point to remember is that the point of the standards is to show
how a large group of children grow, and to enable people like myself to
compare *average* growth of groups of children to the standards.  They were
not designed to be anything more than a general guideline for the growth of
individual children, and are *often* misused and misinterpreted by doctors.
Most MDs learn very little or nothing about growth in medical school -
they're just handed the charts and told "use this to check child's growth."