[Solved] During middle adulthood, the most likely impact of thyroid hormones would be to A) generate growth spurts. B) help metabolize food. C) create myelin. D) drain reserve capacity. Havelock Ellis: A pioneering British sexologist and author known for his studies and writings on human sexuality in the late 19th and early 20th centuries. Masturbation: The act of self-stimulation of one's own genitalia, frequently leading to climax. Krafft-Ebing: refers to Richard von Krafft-Ebing, a 19th-century psychiatrist and author known for his research in human sexuality. Human Sexuality: An area of study and aspect of human life that encompasses sex, gender identities and roles, sexual orientation, eroticism, pleasure, intimacy, and reproduction.