I am a senior science educator at a private college. I am not American and this is a GCE A Level school although it is not in the UK. The exam boards are British and our school does not grade any exams for the end of year exams used for university entrance and they are graded by the British exam board. As a result class tests do not have a significant impact on university admission besides sometimes on predicted scores used before a student obtains their actual scores.
I am in charge of science extracuricular activities at the school and how it usually works is the students that get to represent the school at national events are selected by the school. Typically I use class performance for this but I am allowed to use other factors. This is an elite school and almost all students do very well. But in recent years the percentage of girls performing beyond expectations, with near perfect scores in science has become more than that of boys as they are more focused.
To balance things out I want to select an almost equal number of boys and girls by considering how each group performs compared to their own group's average. This way boys will not be disadvantaged. In our school, the amount of boys and girls in science is almost equivalent and there is no issue with girls not taking maths and science. Almost all of these students will end up getting good grades with a mix of A and A\* for their GCE exams anyway and will get into the best universities around the world. However extracuriculars are considered by some really elite universities like Oxford, Cambridge and American Ivy's.
WIBTA if I did this?