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Using data from the Fels growth study, we show that individual curves for growth in recumbent length from one year to maturity can be represented in good approximation by the sum of two logistic components. The first component describes growth occurring throughout the prepubertal period and continuing in some degree until maturity; the second describes the adolescent growth spurt. The components are functions of six parameters, five of which are estimated by non-linear least squares, and the sixth is the mature stature taken directly from the data. A reliability analysis of the parameter estimates for the Fels samples shows that most of the individual differences in growth pattern, within sex, can be attributed to three, or at most four, of the six parameters. Distributions of estimates of these four parameters are presented and discussed in relation to sex differences.