At birth, all children are characterized by different values of body weight and body length, caused by both genetic factors and the conditions and characteristics of their prenatal development. It is important to investigate whether these differences expressed at birth, particularly those values that are below average, can be improved by implementing a six-month period of kinesiological activity during childhood. With this purpose, a research was conducted using a sample of 214 children, aged 6,13 +/- 1,04 decimal years (experimental group of 93 boys and 29 girls, control group of 43 boys and 49 girls), which was divided into two subsamples by using K-mean cluster analysis based on body weight and length of children at birth. The formed subsamples were defined by the average values of the applied variables as groups of children that were below average and above average, according to their development at birth. Motor status of children was assessed by using a battery of 7 standard motor tests, and intellectual status by applying Raven's Colored Progressive Matrices. Quantitative effects of the applied kinesiological treatment were analyzed based on the initial and final status of young participants in the examined variables by using multivariate analysis of variance and covariance. Qualitative differences were defined by results of factor analyses. It was established that there were no statistically significant differences in the variable space between boys and girls in the initial measurement, in relation to the experimental and the control group, so the sample was further treated as the overall sample of children. The effects of the experimental treatment have shown significant improvement of motor and intellectual functioning of children in the experimental group of children with below average and above average development at birth.