Biochemistry uses molecular methods to study chemical processes in organic systems. Physiology is the study of integrated function among organisms, organs, cells, and molecules in bionetworks and ecosystems. Biochemistry and physiology explain some – though not all – of the many dimensions of sex and gender. Contemporary research in biochemistry and physiology has advanced significantly beyond the monocausal explanations of sex and gender that once dominated these fields. Scientists have come to define sex as anatomically multidimensional and molecularly polygenic.