When a baby is born, the obstetrician or midwife announces “It’s a boy” or “It’s a girl.” As toddlers, children learn to classify everyone as either boy or girl. When our firstborn was very young, we overheard her talking to herself as she grappled with the concept:
Let’s see… I’m a girl, and Kimberly [her baby sister] is a girl, and Mommy’s a girl… but Daddy’s not a girl… He’s a boy. [Pause followed by exasperated sigh] Cause he doesn’t know any better!
As with most things in science, the concept of boy versus girl is more complicated than it appears at first glance. It’s not a simple dichotomy. We humans like to classify everything into neat pigeonholes, but Nature’s inventiveness outsmarts us at every step.
Etymology and meaning of the word gender
Gender originally meant “kind.” The English word was derived from the Latin word “genus” via Old French. In common use, it came to denote masculinity and femininity. Its main application was in grammar, where words were classified as having masculine, feminine, or neuter gender. In 1926, Henry Fowler argued that it was a purely grammatical concept that should not be used in other spheres. In today’s dictionaries, one of the accepted definitions of gender is as a synonym for “sex.” The words are often used interchangeably, although the preferred usage is to use sex to refer to biological differences and gender to refer to social roles. (Which becomes problematic when you’re not sure if a given trait is determined by biology or culture.) The modern academic sense of gender was popularized by the feminist movement. As a result, scientists have sometimes chosen to extend the use of the word to biological differences in an attempt to show their sympathy with feminist goals. Some have even argued that “sex” is a just another social construct.
Many factors combine to determine sex and gender, and not one of them is simple black and white
Chromosomal sex. Males are XY, females are XX. But there are individuals who are XXY (Klinefelter syndrome), XYY, a mosaic of XX and XY cells, XXX, XO (Turner’s syndrome), and various other accidents of cell division gone awry. How are these anomalies to be categorized? How do they affect behavior and gender role?
Intrauterine hormonal effects. In congenital adrenal hyperplasia (CAH), a female fetus (XX) is exposed to high levels of adrenal hormone and is born looking like a boy. In androgen insensitivity syndrome (AIS), a male fetus is unresponsive to androgens and is born looking like a girl. In 5-alpha reductase deficiency (5-ARD), androgen levels are normal but an enzyme necessary for male genital development is missing; these individuals may appear to be female and may be raised as girls, but at puberty they develop masculine secondary sex characteristics.
Internal sexual organs. Are there testes or ovaries? Both? Is there an ovotestis?
External sexual characteristics. Is there a penis? A vagina? Both? Neither? An enlarged clitoris? Hypospadias? In concealed penis, a penis is normally developed but hidden from view under fat in varying locations. In 1 in 10 million male births, there is aphallia: a failure of the penis to develop in an otherwise normal XY fetus.
The sex of rearing. Was the individual raised as a boy or a girl? Even this isn’t so straightforward. In the case of 5-ARD, if it is known they will develop the appearance of males at puberty, rearing may be ambiguous. John Money’s famous patient, a boy whose penis was amputated in a circumcision accident at the age of 8 months, was raised as a boy for 17 months before he was re-assigned to a female gender and raised as a girl. (That didn’t work out too well!)
Sexual desire. Is the individual attracted to men, women, both, neither? To children, animals, or fetish objects like shoes or cars? Is suffering or humiliation a turn-on? Are non-consenting partners preferred? If you think you know about the wondrous variety of sexual interests, check out this list of paraphilias and you may discover a new one. I was intrigued to discover plushophilia, the sexual attraction to stuffed toy animals.
Sexual behavior. Does the individual act on those sexual desires or suppress them?
Social gender. Does the individual play the role expected of a male or female in society? All the time, or part of the time? Does he/she sometimes dress in clothes of the opposite sex, publicly or in secret? Do friends and associates perceive the individual as male or female?
- The bathroom test: does the individual go through the door marked “men” or “women”? Do the other patrons object?
- The language test. Does the person refer to himself/herself as a man or woman, Mr. or Ms.? Does he/she prefer others address him/her as “he” or “she”? (In the case of androgynous uncertainty, it’s OK to ask which they prefer.)
Legal gender. My former secretary Doris’ birth certificate mistakenly listed her as male; she only succeeded in getting the error corrected after she had become a grandmother. Gender can be legally changed after sex-change surgery. The laws may make different provisions for males and females (draft registration, maternity leave), and may prohibit same-sex marriage. Pension systems often have different retirement ages for men and women.
Gender dysphoria. Does the individual feel he/she was assigned the “wrong” sex? Is it a mild discomfort or an overwhelming conviction? Does it lead to changes in behavior?
Surgically altered external genitalia. What do we call someone who has undergone sex change surgery? What do we call someone who wants the surgery and is waiting for it? At what point in the long sex-change process can the sex be assumed to actually have changed?
Are there parallels in animals?
There are examples of intersex and sex chromosome abnormalities in animals. Homosexual behaviors have now been reported in 1500 species of animals. In animals, particularly fish, there are examples of organisms that are born as a male and change sex to become a female, and vice versa. There are also bidirectional sex changers that have both male and female gonads and change sex according to social status. Animals have frequently been observed attempting copulation with animals of other species.
Sex is a spectrum on several axes
Science has not been able to categorically distinguish a male from a female. There’s no one simple test to determine whether an individual is a woman or a man. It’s not an either/or dichotomy, but a multidimensional spectrum on several axes, from the biological to the social to the psychological. And science has not conclusively shown which characteristics are biologically determined. Nature and nurture interact and influence each other; it’s difficult to tease out the contributions of each. Each axis has its own continuum, with degrees of strength. A person can fall at the male end of the spectrum on some axes and at the female end of the spectrum on others.
So what are we to do? Reject the very ideas of sex and gender and stop trying to classify people? Reject the dichotomy? Of course not! The binary classification is sufficient for most practical purposes and is very useful. In medicine, the knowledge that a patient is male or female helps to guide diagnosis and treatment. We know that men and women have different responses to medications and different incidences of various diseases.
It is enough to remember that male/female categories are arbitrary and not absolute. Science is not simple. We try to categorize, but nature is infinitely inventive.
This article was originally published in the Science-Based Medicine blog.
