Human sexuality plays a major role in everyone's life. Regardless, whether we are young or old, male or female, American or Japanese, it is an integral part of what we do and who we are as a human species. After sleeping and eating, it seems to be one of the most important motivations we face as human beings. That is, it takes up so much of our thinking and behavior that it sometimes seems like every facet of our lives revolves to some extent around it. Human sexual behavior is different from that of other animals, in that it appears to be governed by a variety and interaction of different factors. In other words, while “lower” animals or species are driven by a “force” to reproduce and therefore participate in sexual behavior. Charles Darwin's position on evolution is based on reproduction. Without reproduction, there would be no way to explain natural selection or survival of the fittest. The idea that sex functions to provide variation on which natural selection can act was first advocated by August Weismann and has since dominated many discussions of sex evolution and recombination. With Darwin's theory of evolution, the purpose of this article is to further expand the idea that the purpose of human sexuality is reproduction, and how homosexual activities would contradict this theory of evolution presented by Darwin through its four principles of evolution. Dialogue on human sexuality is not possible without first addressing the biological perspective, particularly that of hormones (Strong, DeVault and Sayad, 1996). Hormones can be considered one of the main “driving forces” of sexual behavior. In recent years, there has been a lot of research around examining the different roles in the middle of the article...... "The origins of human sexuality: procreation or recreation?." Reproductive Biomedicine Online (Reproductive Healthcare Limited)18.S1 (2009): 50-59. Premier Academic Research. Internet. April 11, 2014. Brooks, Rob. “New ideas about the evolution of same-sex attraction.” The Huffington Post.TheHuffingtonPost.com, December 14, 2012. Web. April 13, 2014. Charlesworth, Brian. “Anecdotal, historical, and critical perspectives on genetics Darwin and genetics.” Genetic. Np, and Web. April 13, 2014. Spinelli, Ernesto. “Being sexual: human sexuality revisited.” Existential Analysis: Journal of the Society For Existential Analysis 24.2 (2013): 297-317. Academic researchFirst. Internet. April 11, 2014. “Study finds epigenetics, not genetics, underlies homosexuality.” » Study finds epigenetics, not genetics, underlies homosexuality. Np, December 11, 2012. Web. April 11. 2014.