I am investigating a common discrepancy between male and female self-reports on a survey about sexual experiences. Generally, women report ~2/3 higher rates then men do. I have modified the survey and now need to find out if/how the discrepancy between males' and females' reporting rates may have changed. Males and Females each fill out both verisons (modified and original) of there gender-specific survey. So, what i want to compare is the difference between male-and-female difference scores on the original survey, and male-and-female differences on the newer/modified survey. What specific statistical test could I use here?