Freud's theory and the basis of the superego explanation is subject to gender bias. Freud said that girls have a weaker superego, as they don't experience the same intense castration anxiety, so they have less pressure to identify with their same-sex parent. Therefore, according to Freud, girls are more likely to offend. However, Hoffman studied children being asked to resist temptation and found no gender differences, if anything girls were more moral. This questions the explanatory power of the superego, limiting the validity.