This paper will argue that until recently the terms sex and gender have been virtually synonymous when referring to the classification of human beings as male or female. Further, this understanding should be retained or recovered rather than adopting an understanding that splits sex and gender into two non-overlapping concepts. This synonymous understanding runs counter to new definitions asserted by advocates of transgender ideology in which sex and gender are considered to be distinct concepts that may be detached from one another. In transgender ideology, the concepts of sex and gender were first distinguished from each other then detached from each other. In a final step, as Ryan Anderson (When Harry Became Sally, 2018) and Robert S. Smith (The Body God Gives, 2025) have pointed out, the concept of gender has been made to displace biological sex so that subjective gender now defines biological sex rather than the other way around. In contrast, many conservative evangelical and Catholic theologians resist allowing sex and gender to be detached from each other, yet often still accept sex and gender as distinct concepts. For example, in opposition to transgender ideology Smith argues that gender is anchored in biological sex, but that it is still “advantageous to distinguish gender from sex” (p. 153).
Although in agreement with most of Smith’s project, this paper will argue that it is better to push back further and avoid splitting sex and gender into two distinct concepts. Rather, sex and gender may often be used interchangeably. Historically understood, the concept of gender may be more expansive than biological sex, but in reference to humans it is never less than biological sex and always includes biological sex. We will demonstrate this based on etymology, historical definitions, and common usage. Etymologically, the term gender is derived from the Greek root gen which has to do with biological reproduction. The English word gender was used as a grammatical term for the classification of words in a sense analogous to gendered reproduction. In the 20th century, the word gender came to be used more frequently as a polite replacement for the word sex because the word sex came to be used more often as shorthand for sexual intercourse. Thus, gender should be understood as a classification based on the mode in which one is biologically structured to generate new life.
Finally, this paper will show how this understanding of gender avoids a miss-step and brings clarity to current debates regarding sex and gender. Teachers should help students see that the differentiation of sex and gender asserted in transgender ideology is new and artificial. Rather than adopting a new definition of gender that only refers to that which is subjective and/or cultural, we should encourage the historical use of sex and gender as virtual synonyms. The subjective or cultural aspects of gender can be adequately expressed instead by phrases such as gender identity, gender expression, gender roles, or gender expectations.