What are the implications of Darwin’s theory of evolution through natural selection for thinking, prejudicial or otherwise, about foreigners, race, Jews, sexual orientation, and women? Did Darwin himself, caught in Victorian prejudices, have any awareness of the full implications of his theorizing?

This chapter reviews what can be gleaned about human sexuality from the evolutionary and ethnographic record. Ancestral human sexuality leaves neither fossil nor archaeological evidence, but inferences about how humans mated, consorted, parented, formed partnerships, and aggregated into families can be drawn from two large and growing bodies of work, both discussed in this chapter. The first are anatomical and biological indicators of ancestral mating patterns inferred from fossil evidence as well as observations from nonhuman primates. The second is ethnographic research across an array of contemporary human societies, which highlights variation in mating, marriage, and family structure. Together, biological indicators and cross-cultural patterns shed light on the legacy, constraints, and possibilities carried forward into the diverse and variable expression of human sexuality today. Humans have a deep ancestry in a social structure of males and females living in social groups together, although how humans organize themselves is structurally different from anything observed in our closest relatives. Not only do families form around long-term pairbonds in all societies, but there is also a great deal of flexibility in who constitutes the pairbond, the families that surround them, and in the prevalence of extra-pair relationships.

Gender–sexuality alliances (GSAs) are school-based clubs that provide space for LGBTQ+ youth and their heterosexual cisgender peer allies to socialize, build community, provide social-emotional support, access LGBTQ+-affirming resources, and advocate against discrimination. In this chapter, we review the historical underpinnings of GSAs; their contemporary roles in schools; the ways in which GSAs harness their collective power to advocate and promote social justice for LGBTQ+ people; the ways in which youth experience empowerment through their GSA involvement; and how GSA research can be used by school administrators, GSA advisors, and youth leaders. Finally, we highlight avenues for future research that could further aid GSAs in their aspirations to promote thriving among their members and social justice in their schools.

That differences in health outcomes exist between groups is unsurprising and, in some cases, seems subject to ‘natural law’. Such ‘common sense’, arguably unavoidable differences are termed ‘health disparities’ – a term usually understood to be value-neutral. By contrast, more complex differences in health outcomes which seem to derive from differences in opportunities or systemic bias are deemed ‘unfair’ and are referred to as ‘health inequalities’ or ‘health inequities’.

This chapter delves further into how we describe health inequalities and different measures and data that illustrate these differences. Causes and mechanisms of inequality are explored, followed by examples of inequality across groups with certain population characteristics, including ethnicity; gender, sexual orientation and gender identity; disability; and socially excluded groups. Finally, approaches and strategies for reducing health inequalities are presented, with potential actions described at the micro-, meso- and macro-levels.

Chapter 6 summarizes the changes to medical care in recent years. There is now a greater recognition that the projected social and psychological challenges of genital variations cannot be fixed by surgery. The first international consensus statement on intersex was published in 2006. The statement makes a number of recommendations to improve care. Controversially however, a new term disorders of sex development (and, later, differences in sex development, or DSD) was introduced to replace intersex and hermaphroditism. Biotechnological developments have been advancing rapidly. More has been learned about “normal” and “abnormal” sex development. However, parents still struggle to talk to children about their bodily variations, young people still worry about getting into relationships, childhood genital surgery is still considered the only way out of stigmatization, psychological expertise is still a low priority in specialist services and the huge potential of peer support is not fully realized.

How to talk about variations in sex development is a major theme for impacted individuals and families. This is the topic of Chapter 12. The author summarizes the research literature with caretakers and with adults about the difficulties of disclosure. Considerable criticism has been levied at health professionals for failing to role model affirming communication. For sure there are gaps in health professionals’ talk, but the biggest contributor to the difficulties is to do with the widespread misunderstanding about the biological variations. Psychological care providers are not there to put a cheerful gloss over clients’ negative expressions. However, they can be part of the favorable social condition in which a wider range of meanings about bodily differences are negotiated. In the practice vignette, the author highlights how tentative and uncertain the enabling process is, where a negative view of sex variations is still widely endorsed in the social context.

In a gendered world, doctors and caretakers took for granted that making atypical bodies more typical was a humane way out of a difficult situation for child and family. Had the professionals carried out proper research, they would have learned from their young patients that the approach was physically and psychologically risky. But research on the long-term effects was not carried out, certainly not from the patients’ perspective. There was also no comparison group made up of people growing up with unaltered genital variations. Research with adults is the topic of Chapter 4 of this book. Since the 1990s, a number of outcome studies with adults have identified many problems of childhood surgery, such as multiple operations, scarring, shrinkage, sensitivity loss, unusual genital appearance and sexual difficulties.

Chapter 8 begins by pointing out the current lack of collective clarity about the role of psychological care providers (PCPs) and suggests that researchers and practitioners make collective effort to develop the role of PCPs in sex development in future. Meanwhile it outlines the psychological consultation process that is generic and familiar to most PCPs. The author provides an initial assessment template and summarizes the popular psychotherapeutic interventions. The template is visible in several of the practice vignettes in the ensuing chapters of the book. The author ends the chapter by arguing that the tertiary environment is set up for diagnostic workup and treatment and unsuitable for the kind of ongoing psychosocial input that is needed by individuals and families living in their communities. The author makes a case for PCPs in DSD centers to collaborate with peer support workers to enable nonspecialist providers in the community to contribute to ongoing support for individuals and families.

Chapter 2 begins with a brief summary of typical embryonic development of the urogenital and reproductive systems. Where the sex chromosomes, reproductive organs and the genitalia in combination do not fit the social categories of female and male, doctors and scientists used to call these physical outcomes hermaphroditism and intersex. They debated for a long time on the “true sex” of the individuals but could not agree on which of the biological sex characteristics should count as their true sex – should it be the sex chromosomes, the gonads or the genitals? Although in the age of genetics, much more is known about how the atypical features have developed. At the same time, people who are impacted by the variations are increasingly disputing medical framing of their differences. The twenty-first century was to seed a new and ongoing debate between the new medical term, differences in sex development (DSD) and intersex, which is now reclaimed by many impacted adults.

Chapter 11 of the book reviews potential psychological contributions in the highly charged process of assigning legal gender to a newborn with genital variations. Although a number of psychological theories exist for understanding gender development, it is the brain gender framework that has been singularly privileged in intersex and DSD medicine. However, the decades of research cannot contribute to the certainty professionals and caretakers seek. Psychological care providers (PCPs) have other frameworks to draw from in order to work ethically and pragmatically with families. In the practice vignette, the author envisions how a highly skilled PCP in a high-functioning DSD team could work substantially to help caretakers to cope with uncertainty and minimize the need for psychosocially motivated medical interventions. In the vignette, the psychological care path is in position before medical investigations begin. It remains highly active long after the medical and legal processes are completed. Although the vignette is built around a child diagnosed with 17β-hydroxysteroid dehydrogenase-3 deficiency, the care principles are relevant to legal binary gender assignment for children born with a range of sex development variations.

Not all sex variations are apparent at birth. Sometimes they are internal and therefore not visible, that is, children are born looking like a typical boy or girl. The child may be brought to medical attention much later, for example when puberty does not follow the expected path. Many of these care users were not told the truth about their biological variation because adults believed that the information would harm them. At the same time, the care users also noticed that they were fascinating to health professionals, who may examine them in droves. Some of them did not discover the truth about their diagnosis and the treatment until mid-life.

For children whose external genitalia look different, when surgical safety and techniques improved, it became routine to align the urogenital anatomy of newborns and young children to the assigned gender. The gender-genitalia alignment was believed to be important psychologically for child and family. Because surgeons found it easier to feminize than masculinize the genitalia, most babies with genital variations were assigned female. From the 1990s, some of these adults have spoken out, talking of too many operations, been too often examined by too many and not understanding what was happening.

Inconsolable distress is neither a universal nor inevitable response to inability to have biological children. In Chapter 14, the author criticizes research with clinic samples that has produced a problem-saturated account of childlessness that obscures a wide range of alternative responses. The author examines the influence of pronatalist ideology on people who are impacted by infertility including many people with sex variations. Away from the treatment context, psychological input can guide individuals, couples and groups to explore personal meaning of nonparenthood. It can facilitate service users to grieve for what is not possible, challenge feelings of deviance and shame, reengage with a range of life goals and, perhaps most important of all, recast adult identities. Through the practice vignette built around a heterosexual couple, one of whom has a late diagnosis of Klinefelter syndrome, the author teases out the difficulties of working psychologically in a treatment context, where complex existential issues and relational dynamics are compressed into the frame of pressurized treatment decisions.

Psychological care is endorsed in DSD medicine. Psychosocial research has been on the increase. But these positive moves have not given psychological practice the kind of collective focus that is enjoyed by the biomedical disciplines. However, psychological care providers have a wide variety of thinking tools and practice techniques to draw on, if to work in an ad hoc way at times. These tools and techniques do not change, but some are more useful and relevant than others for this service context. In Chapter 7, the author discusses the strengths and weaknesses of key theoretical frameworks in healthcare psychology. A major weakness of the individualistic models is their lack of capacity to address structural inequalities in psychological wellness and distress. The author introduces aspects of the Power Threat Meaning Framework and describes how to draw from its theoretical richness to think systemically about what sex variations pose to individuals and families in the social context and how they are responded to. The Framework provides the theoretical backbone for some of the practice vignettes in the final section of the book (Chapters 9–14).

In the 1990s, some former patients mounted street protests in front of medical conferences to draw attention to their trauma. They reclaimed intersex as a personal identity and campaigned for healthcare reform. These developments are the focus of Chapter 5. Intersex is coming out of the closet more and more, through being a topic in television documentaries, novels, films and art. Intersex activists challenge medical authority to change practice. Furthermore, they are not waiting for doctors and scientists to come to their viewpoints. They have successfully lobbied human rights agencies to position childhood genital surgery as a violation of their human rights. They demand that surgery is delayed until the child can give informed consent or is at least old enough to participate in the discussion and offer their agreement.