G Gender Identity: From Biological Essentialism Binaries to a Non-binary Gender Spectrum Sandra Hopkins 1 and Luca Richardson 2 1 International Thriving at Work Research Group, University of Chester, Chester, UK 2 Institute of Gender Studies, University of Chester, Chester, UK Definition Gender is a socially constructed paradigm whose purpose is to differentiate between the biological sexes. From a sociological perspective, gender is separate to sex and is a socially constructed con- cept (Jackson and Scott 2002). More recently, Wood and Eagly (2015) defined gender identity as the social and cultural meanings ascribed to male and female which people incorporate into their own psyche and identities. Gender is viewed as a spectrum rather than a binary of male/female. For some individuals, the gender assigned to them at birth because of their sex may not be the gender they identify with. Introduction Until the late 1960s and early 1970s, it was com- monly accepted by western societies that biological sex and gender were synonymous and fixed. A change began to occur in 1968 when Robert Stoller, a US psychiatrist and psychoana- lyst, undertook work with individuals who had indeterminate sex classification, and this work raised new questions regarding gender (Stoller 1968). In 1972, sociologist Ann Oakley examined his work and concluded that sex and gender were distinct and separate: “Oakley defined sex as the anatomical and physiological characteristics which signify biological maleness and female- ness, and gender as socially constructed mascu- linity and femininity” (Jackson and Scott 2002, p. 9). Oakley was part of the new vanguard of sec- ond-wave feminist academics who were proactive in bringing the notion of gender into sociological research methodology, whereas, previously, it had been absent. Shilling (2012) explained that until that point, “The body has been absent from clas- sical sociology in so far as the discipline rarely focused in a sustained manner on the body in its own right” (Shilling 2012, p. 8). Since then, there have been numerous articles and books published on gender identities, including Butler (1990), Bornstein (2016), Stryker and Paisley (2014), Halberstam (2016), and McNabb (2018). A Brief History of Gender If gender is a social construction, then the mech- anisms used to create, maintain, and impose gen- der roles need to be better understood in order to © Springer Nature Switzerland AG 2020 W. Leal Filho et al. (eds.), Gender Equality , Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-70060-1_87-1