In reviewing the growth of infants who live under favourable conditions and are fed according to WHO feeding recommendations, the Working Group found significant differences between the growth patterns of these infants and the patterns reflected in the NCHS-WHO international reference. Given the short- and long-term consequences of growth failure, and the dangers of both the premature introduction of complementary foods and their undue delay--described as the "weanling's dilemma", the Working Group concluded that use of the current NCHS-WHO reference appears to accentuate the difficulty of avoiding these extremes rather than to help ensure optimal infant nutritional management. The Working Group identified the following requirements: (a) a new reference which will enhance the nutritional management of infants; (b) the reference population should reflect current health recommendations because of the frequent use of such reference data as standards; (c) evaluation, in a broad range of settings, of the practical utility of using reference data based on infants for whom the WHO feeding recommendations are being followed; (d) close investigation of the effects of different complementary foods on the growth of infants who are being fed according to the WHO recommendations; (e) criteria for evaluating abnormal growth patterns; (f) research for identifying proxy measures for length; and (g) evaluation of reference data based on other anthropometric measurements, such as skinfold thickness and arm and head circumferences.