In 1904, physician William Henry Walling published Sexology, a family medicine reference book. In his book, Walling proposed that his guidance would help people who were married or single and young or old, as well as anyone who wanted to conform to, what he claims are, gender expectations. Sexology discusses issues such as masturbation, abortion, pregnancy, labor, and marriage. Despite Walling’s limited scientific explanations and evidence for his medical claims, the Puritan Publishing Company printed and distributed the book, which received many positive reviews and endorsements from other physicians, college presidents, politicians, and religious leaders. However, in the twenty-first century, people may consider many of Walling’s claims to be sexist and oppressive toward women. Sexology provides readers with examples of historical medical misconceptions of male and female anatomy and provides context for the logic of reproductive medicine at the turn of the twentieth century.

In the United States, most people are assigned both a biological sex and gender at birth based on their chromosomes and reproductive organs. However, there is an important distinction between biological sex and gender. Biological sex, such as male or female, commonly refers to physical characteristics. Gender refers to the socially constructed roles, behaviors, and actions people take on, usually in relation to expectations of masculinity or femininity. As of 2022, there is disagreement over the relation between sex and gender. People’s biological sex and gender greatly influence the way they understand themselves, as well as how others treat them and how they interact with society. Moreover, some people’s gender differs from what they were assigned at birth, and they face discrimination, harassment, and violence. Evolving understandings of gender and sex in the US have created more ways for people to live and express their gender identities.