IntroductionThe subject of differences between the sexes must naturally be approached with caution in our modern world. Emotionally charged and fraught with ideas about political correctness, gender can be a difficult topic to discuss, especially when discussed in correlation to behavior and social behavior. Throughout history, many people have struggled to understand what made men and women different. Until the modern era, this topic was generally left to religious leaders and philosophers to discuss. However, with the acquisition of more specialized medical knowledge in human physiology and the advent of anthropology, we now know much more about sex differences than at any other time in history. However, many of our questions remain. The purpose of this article is to discuss the physical aspect of sex differences in humans, otherwise known as sexual dimorphism, the evolutionary history of our species, and some associated behavioral and societal trends. . To do this, I will begin by describing the anatomical structures commonly used to measure sexual dimorphism in our species. Having established these criteria, I will expand on the evolutionary history of sexual dimorphism in humans, beginning with Oligocene anthropoids and ending with current trends. I will conclude this article by discussing some of the behavioral traits thought to correlate with varying degrees of sexual dimorphism and their plausibility. Anatomical Structures Used to Study Human Sexual Dimorphism To discuss sexual dimorphism, one must first define the term. Webster's Dictionary defines sexual dimorphisms as "the condition in which differences are...... middle of paper ......Bindon, Jim2004 Fossil Hominids. ANT 270 Notes.http://www.as.ua.edu/ant/bindon/ant270/lectures/hominids1.pdfDelson, Eric1981 Paleoanthropology: Pliocene and PleistoceneHuman evolution. Paleobiology, 7:3:298-305. Frayer, David W. and Milford Walpoff1985 Sexual dimorphism. Annual Review of Anthropology, 14: 429-473 Key, Catherine A.2000 The Evolution of Human Life History. WorldArchaeology, 31:3:329-350.Mitani, JC et al1996 Sexual dimorphism, operational sex ratio and intensity of male competition in polygamous primates. The American Naturalist, 147:6:966-980.Rogers, Alan R. and Arindam Mukherjee1992 Quantitative genetics of sexual dimorphism in human body size. Evolution, 46: 1: 226-334.Wolpoff, Milford H.1976 Some aspects of the evolution of sexual dimorphism in early hominids. Current anthropology18:4:579-606.