It is not just data. Sometimes our definitions fall short. Take, for example, the way we view income and labor. It simply doesn't cover enough of the work that women, and in particular poor women, are doing -- especially in their own households and the vast "informal" economy in which most of the world's poorest people work.
Refusing to acknowledge the impact of biology and innate gender differences on behavior within relationships seems to me to be unnecessarily shooting couples in the foot; why not discuss something that would likely resonate with them and would help them understand the evolutionary and biological explanations for each partner's behavior?