The hypothalamus and structures of the limbic system are important in sexual behavior and motivation. There is evidence to suggest that our motivation to engage in sexual behavior and our ability to do so are related, but separate, processes. Alfred Kinsey conducted large-scale survey research that demonstrated the incredible diversity of human sexuality. William Masters and Virginia Johnson observed individuals engaging in sexual behavior in developing their concept of the sexual response cycle. While often confused, sexual orientation and gender identity are related, but distinct, concepts.