Girls and boys start off equal in mathematics and science performance and interest in school. They appear to do equally well in both subjects in elementary school. Once courses become optional in secondary school, the down hill spiral in enrollment of female students in mathematics and physical science begins, accompanied by decreases in achievement and interest. This means that women are inadequately prepared for most college majors as well as those in technical fields. The findings of research, improvements in the situation, and intervention strategies to help increase girls' participation in science are discussed. Several resources for the identification of intervention programs are listed including four national networks of women in science and engineering. A list of 12 references is provided. (CW)