Variable Name       | Description | Gender | M = Male, F = Female | WT2 | Weight of the child in kilograms at age 2 |
HT2 | Height of the child in centimeters at age 2 | WT9 | Weight of the child in kilograms at age 9 |
HT9 | Height of the child in centimeters at age 9 | WT18 | Weight of the child in kilograms at age 18 |
HT18 | Height of the child in centimeters at age 18 |