Two studies examined the roles of altruistic values, egalitarianism, self-efficacy, and perceptions of utility in shaping children's interest in scientific fields. In Study 1, middle school girls attending an intervention program ("n"=617) heard presentations by female scientists (expected to increase egalitarianism), engaged in hands-on science activities (expected to increase self-efficacy), and received information about scientific careers (expected to increase utility value). In addition, girls heard presentations that either (a) emphasized the altruistic value of scientific careers, or (b) made no specific references to altruism. Comparison girls ("n"=105) and boys ("n"=69) attended the same middle schools as intervention attendees, but did not attend the intervention program. Results from Study 1 indicated that girls who believed more strongly in the altruistic value of scientific careers scored higher on the self-efficacy and utility measures than their peers. Further, belief in the altruistic value of science predicted interest in science. Study 2 replicated these findings using a pre-and posttest design.