Physical examination: Pubertal staging according to Tanners classification of boys, genitalia development (G1-G5), pubic hair development (PH1-PH6), axillary hair (yes/no), axillary sweat (yes/no), gynecomastia (yes/no), micropenis (yes/no), height, mother height, father height, target height, weight, BMI, bone age and predicted adult height.