findings and they have been subject to numerous critiques, centering on their scientific standing and their harmful implications. For example, Hegarty (1997), in a feminist interrogation of Le Vay's work, points out that Le Vay's dichotomous view of sexuality excludes those with “bisexual or queer” sexual identities. A view that homosexuality is fixed in structures of the brain reinforces the view that it is a constitutional deficiency that is universal in all homosexual men, and ignores the variety and mutability in the expression of human sexuality. As Hegarty notes, lesbian and gay people “differentiate their sexualities in complex and different ways across the life span” (1997, p. 356). Hegarty sees LeVay's work as a typical example of biological essentialism, “part of a longer ongoing attempt to inscribe sexual desire within the discipline of biology” (1997, p. 355).
Many different biological and social explanations of sexual orientation have been put forward, ranging from genetic differences to atypical early attachments with parents, but the general consensus is that while biological factors, operating via the genes or postnatally, may have a role and social factors may also have a role, sexual orientation is multiply determined and may have very different causal origins across the population (APA 2008).
An essentialist position on sexual orientation sees it as a fixed and unchanging trait of the individual. In his historical review of sexuality studies, Plummer comments that the Kinsey Institute and others in the 1970s “moved sexuality from being seen as essentially biological and reproductive to the challenge of taking seriously its socially grounded multiple meanings” (2012, p. 245). Plummer continues, “sexualities are never fixed or stable, they do not harbour one grand truth and they do not reveal our essential nature” (p. 253). He notes that by the 1990s and the publication of books such as Simon's Postmodern Sexualities (1996) scholars increasingly adopted a social constructionist perspective on sexuality, As Plummer notes sexuality was “destabilized, decentered, and de‐essentialized” (2012, p. 247).
However studies show that although scholarly thinking on sexuality may reject an essentialist perspective, essentialist thinking may still be a part of how many lay people conceptualize their own sexual orientation. Fausto‐Sterling (2012b) gives the example of a study by Stork which showed that women who have entered lesbian relationships in middle age – after having been married and having had children – tend to conclude that they must always have been a lesbian but just didn’t know it (1998).
Diamond introduced the term “sexual fluidity,” which she claims is more common in women than in men (2009). One of her studies, which study tracked young women who identified as having a same‐sex orientation into middle age and older found considerable fluctuation in their sexual preferences and behavior over time, often prompted by changes in context and opportunity (Diamond 2009). Diamond argues for a de‐essentialized, social constructionist perspective on sexual orientation which is against both biological determination and the idea that a person's sexual preference is necessarily fixed across the life course. Despite the increased discussion of sexual fluidity in academia and in the media, accompanying the higher profile for gender fluidity, empirical research indicates that the majority of people retain the same sexual orientation/preference across the life course (Savin‐Williams et al. 2012).
A Place for Biology but not for Determinism or Essentialism?
Reclaiming the Body
For many years there was a widespread rejection within feminism, across all its manifestations, of any form of theory that included biological elements. To see any female characteristic as biological in its origins or mode of functioning was seen as tantamount to accepting that it was fixed and immutable. Biology and essentialism were thus seen to go hand‐in‐hand. In the late twentieth century, with the rise of social constructivist theory and the accompanying “linguistic turn,” the body and its functions were seen as texts where discourses about the body – often positioned as oppressive and unhelpful discourses – dictate what is experienced by the individual. Thus “the thought body” became a theoretical preoccupation for many feminist scholars and the material body remained problematic (Greene 2015). Although the shift to seeing social and discursive factors as the causes of difference and therefore the target for change was understandable and productive, one consequence was the exclusion of the physical from consideration and the perpetuation of culture‐nature, mind–body binaries. Also, as Grosz comments, social constructivist perspectives reduced “materiality to representation” (Grosz 2005, p. 172). In relation to sexuality, Plummer comments that the predominantly social constructivist view of sexuality has served to take attention away from the body and bodily acts but he notes a recent increase in interest in research into the embodiment of sexuality and forms of sexual expression (2012).
Ussher was among a number of feminist theorists who felt uncomfortable with this preoccupation with the discursive alone and argued accordingly for the need for a material‐discursive perspective (2006). In this century a number of feminist scholars have reembraced the material and the biological and there has been a return to some form of acceptance of the material reality of the body, with material‐discursive approaches and “the new materialism” becoming more popular (Barad 2003; Hird 2004). Such work resonates with the work of critics of mechanistic and reductionist perspectives within biology who are associated with the emergence of “the new biology” (e.g. Woese 2004). Importantly, the “new materialists” and cognate theorists have found ways to resist any form of biological determinism.
Currently, biological determinism is under attack from feminist scientists, from those who favor sociocultural determinants but also, even more importantly, from those who oppose the very idea that all human behavior is determined, either by biological or by social factors.
Explaining the Role of Biology
There are some contemporary theorists who attempt to take account of the biological in their approach to understanding what shapes sex and gender‐linked behavior. The basic premise behind these theories is that human life is complex and should be seen from a biopsychosocial perspective. One hypothesis is centered on the fact there are some physical and physiological differences between the sexes that are both evident at or shortly after birth and more or less universal (Eliot 2009). These relatively small but consistent differences are mostly to do with size (males are larger and heavier), activity level (males are more active), maturity (females are more mature physiologically), and vulnerability (males are more likely to die in utero and after birth and are more prone to suffering from a range of childhood disorders). Eliot argues that “each of these traits is massively amplified by the different sorts of practice, role models and reinforcement that boys and girls are exposed to from birth onward” (2009, p. 6).
Although Eliot does not mention the work of researchers in the dynamic systems and relational developmental systems fields, her hypothesis sits quite comfortably with these very active areas of research (see, for example, Overton and Lerner 2012). Fausto‐Sterling (2012a,b) and Martin and Ruble (2009) see dynamic systemic developmental models as offering a more adequate theoretical framework for explaining how gender‐typed traits develop and change over time. This stable of theories works at the intersection of biology and the psychosocial sciences and recognizes the ongoing interconnectedness of biological, social, and psychological processes, adopting a developmental and longitudinal approach to research. Fausto‐Sterling discusses the process of “gender fortification,” which is set in motion as soon as it is known whether the new baby (or baby in the womb) is a girl or a boy. As she says, “the social response to the genitalia of the newborn is intense” (2012b, p. 7). This chimes with Eliot's view that originally small differences are amplified by our social response to them.
Once factors external to the body enter into the picture, i.e. as soon as conception takes place, there is a fundamental inseparability between the biological and the environmental, between nature and nurture. Fausto‐Sterling talks about the ways that external influences become embodied (2012b). This implies that when scientists assess what they claim to be “the biological,”
