One explanation for gender differences in criminality is the idea that women and girls are controlled more than boys and men are. Part of the canalisation of gender roles during primary and secondary socialisation has historically been the comparative freedom that boys enjoy, staying out later and generally being under less informal surveillance than girls. According to Frances Heidensohn, girls are controlled by fathers and other relatives until they are married when they come under the control of their husbands. The fact that boys and young men spend more time away from older or otherwise authoritative figures could account for their higher levels of criminality, especially anti-social behaviour.