The family does not just play the role of primary socialization and moral education of children; it has historically also served as a source of stability, permitting a division of labor and shared resources. Is a family without children still a family? Of course. At least…I think so. Is the dog my wife and I love and care for a member of our family? I would say yes—do family members have to be humans? If dogs count, what about goldfish, or chickens? I mean to suggest that, regardless of theoretical approach, the definition of family is a bit more slippery than it first seems to be. For example, some would define a family as a group who share a common bond and live together. Divorced parents and their children (more on this in the next section) don’t live together; are they still a family? What about “commuter marriages” where a couple are married but live in different states? You’re still a family even if you live apart, right? Are you still a family if you live alone? Others would define “family” more broadly—are not, for example, your great-grandparents or your third cousins are still family, even if you have never met them, or they passed away before you were born, right? Go back far enough, and all human beings, and ultimately, all living things, are related to one another. If we are tempted to define family in terms of biology, then biologically speaking, every form of life on earth that lives or has ever lived, is a family member.

As I mentioned earlier, from about the 1950s up until the end of the twentieth century, social scientists distinguished between sex—something that was biologically “given”—and your gender—what you learned to do, how we learn to be men and women in the context of our respective societies. As we learned more about human beings, the assumption that sex is biologically given came into question. Some people are not born either male or female—a small proportion of babies are born intersex, meaning that biologically, they are born with a configuration of sex organs, hormones, or other markers which is not clearly either male or female. When a baby is anatomically intersex, historically they have been assigned to one or the other sex, and the infant’s body was made, through surgery, to conform to this identity. But with hormones, chromosomes, or other biological elements, many do not find out they are intersex until later in life and may live and die as their assigned sex without ever knowing. So yes, sex is rooted in biology. But it’s another case of average differences with a bit of overlap, a space of uncertainty across one or more biological aspects.