Several studies show that sisters are more likely to be victimized by brothers than vice versa. However, sisters can also abuse brothers, and traditional gender roles can allow such abuse to go unchecked. Schwartz and colleagues found that while women are more likely to use physical aggression during disagreements, parents are more likely to view male aggression more negatively than female aggression, even when the abusive acts are identical (e.g., boys throwing objects during a fight is seen as a more serious transgression than girls throwing objects during a fight). Similarly, Tyree and Malone report that women's violence as adults is more strongly correlated with aggression towards siblings during childhood.