Results of some research performed in Poland have evidenced a relation between the aggressive behaviour of adolescents and the parental attitude perceived by them as improper. According to the results of the earlier studies of authors, significant differences were observed between the levels of aggression manifested by girls and boys and in certain dimensions the aggression of adolescent girls was higher than that of boys. Recently study was undertaken to check the stability of differences related to the sex and aggressive behaviour of adolescents. The research was conducted twice. First in the year 2002 (stage I) and again after 10 years in 2013 (stage II). The data for analysis were collected in the Questionnaire of Perception of Parental Attitudes composed by Plopa and the Questionnaire on Aggressive Behaviour prepared by Wójcik. At the stage I the subjects were 86 young people (56 girls and 30 boys) aged 17 – 19, and in stage II, in 2013, the subjects of the study were 80 adolescents (40 girls and 40 boys) aged 17 – 19. The comparative analysis of the results from 2002 and 2013 has shown a limited stability of relation between the perception of parental attitudes as improper and aggressive behavior of adolescents as well as sexual differentiations of aggressive behavior.