The Brody function had no inflection point. Based on the R2, mean prediction errors (MPE) and residual variances, the Richards function, with a variable inflection point, provided the best overall and the most consistent fit to both sets of data, followed by the Brody function with no inflection point. The Richards was the only function that could predict birth weight with any degree of accuracy. The Logistic and Von Bertalanffy functions, with fixed inflection points, provided poor estimates of actual weights at each end of the growth curve, overestimating birth weight and converging too early leading to underestimation of adult weight or the asymptote. Intermediate weights were reasonably well estimated by these functions. The HE group showed a 28% greater maturing rate compared with the SY based on the Richards function.