Between 1956 and 1965, teachers and counselors in 90 schools used a list of 14 behavioral criteria as guidelines to select 1503 9th graders to participate in a special counseling program for superior students. These Ss' birth orders were compared with census figures, and with chance expectancies based on number of children in Ss' families. Significant overrepresentations of 1st-borns were found for 9 of the 10 yr. and for every family size. Striking similarities were found between the overrepresentation of 1st-borns in this population and groups of college students and eminent persons reported in previous studies. The overrepresentations apparently reflect developmental phenomena which are operative at least as early as the 9th grade. The study illustrates, however, that by the time students reach high school these phenomena may be as much a function of favorable opportunities as they are of favorable characteristics of 1st-borns for achievement. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.