Lec 08 Union - LEC 08 UNION SLIDE TEXT Revised HUMAN SEXUAL RELATIONSHIPS The last two lectures have provided you an understanding of the biological

L EC 08 U NION – S LIDE T EXT Revised - 2008-02-09 H UMAN S EXUAL R ELATIONSHIPS The last two lectures have provided you an understanding of the biological basis of sex and gender through genes, hormones, and environment. It is vital for the survival of the species that the opposite sexes are attracted to each other in order to procreate. Without successful reproduction, the species would gradually die out and eventually become extinct. Therefore it is crucial that the genetic makeup of all species contain the genes for sexual attraction. For you to feel erotic and experience sexual desire for the opposite sex is to ensure that you will play a part in maintaining the continuing survival of the species. However, the reproductive behavior is far more complicated than anyone would have imagined 200 years ago. Studies of human and animal sexual behavior have revealed infinite variations of behavioral strategies employed in reproduction. However, irrespective of how strange some sexual behaviors are, the ultimate goal remains the same—perpetuation of the species. In this lecture, you will find fascinating examples of sexual behavior, as truth is often stranger than fiction. From these examples, you will gain new insights into human sexual behavior. Humans have unusual sexual practices among mammals; human sexual behavior is classified as monogamy—a mating system with only one sexual partner at a time. However, the idea of total commitment to one’s sexual partner is an exception rather than the norm among mammals. In fact, 97% of mammalian species are polygamous, having multiple sexual partners. Chimpanzees, our closest biological cousins, live a promiscuous life style, where everyone engages in sex with everyone else. However, there is a very important reason for this “deviant” sexual behavior, and we will address this later in the lecture. Recent studies in human sexual behavior reveal that human monogamy is more complicated than it seems. There are three types of monogamy: genetic monogamy, sexual monogamy, and social monogamy. In genetic monogamy, the two partners only have offspring with one another. In sexual monogamy, the two partners remain sexually exclusive with one another and have no outside sex partners. In social monogamy, the two partners live together, have sex with one another, and cooperate in acquiring resources in a form of mutual assistance. However, this arrangement does not preclude one or both partners to occasionally engage in sex with outsiders. Genetic and sexual monogamy can be inclusive of social monogamy, but it is not always the case. Throughout history, adultery, prostitution, and other forms of infidelity clearly point to the practice of social monogamy by the human species. Despite the lack of an iron clad relationship, social monogamy is vital in human evolution as well as in the success of the human species. Understanding the evolution of human sexual relationships is critical to the understanding of human nature itself.