by Bruce Dunlavy              (My blog home page and index of other posts may be found here.)

As the issue of same-sex marriage plays out from courtroom to courtroom, the same discussion points are brought up. Is it a matter of rights? If so, whose rights are paramount? Is marriage a religious matter or a legal matter? Is it a property-rights contract or a fundamental foundation of Western society?

As so often proves to be the case in these disputes, the ultimate answer will not be decided by legal or religious thinkers alone. In the end, they will follow determinations of science. If, as some contend, marriage must be between one man and one woman, we must determine which of those two categories each person falls under. Science is proving, however, that it isn’t so easy to make that judgment.

To most people, gender is binary: a person is either male or female.  From the beginning of society it has seemed natural that a person had to be either one or the other. The outward physical appearance of a person has always been presumed to give a true indication of which gender that person belongs to. If sex organs appeared male, that person was male. If sex organs appeared female, that person was female.

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In the middle of the Twentieth Century, modern cellular genetics began to put a new perspective on gender assignment. Scientists determined that the 23rd pair of human chromosomes consisted of either an XX pairing or an XY pairing. The former led to the development of females, the latter to males. At first, this discovery was assumed to give a scientific foundation to the male/female dichotomy, clarifying beyond dispute that there are males and there are females and everyone is clearly one or the other.

Further research, however, confirmed that not all chromosomal arrangements are so cut-and-dried. Some people have more than two sex-determining chromosomes in their 23rd grouping. They may be XXY (Klinefelter syndrome, occurring as frequently as one in 1000 births), XYY, XYYY, or any number of other combinations. Scientists quickly learned that some people’s gender is indeterminate at birth. According to a Brown University study reported by the Intersex Society of North America, persons whose appearance does not conform to the expected standards of male or female represent about one percent of all births. Our traditional ways of defining sexual assignment were inadequate to cover these individuals.

Customary practice led doctors – usually in consultation with the parents of the newborn – to perform some reconstructive surgery to give the baby an outward structure that would fit either a male appearance or a female appearance. The child was then raised as the assigned gender. This is still done in about one in 1000 newborns. [Update: Opposition to gender-assignment surgery for newborns is on the rise, and at least one country has banned it.]

Today much more is known about gender identity – whether a person identifies as male, female, or something else. Experience has taught that just reshaping genitalia will not resolve all the issues. Gender labeling, though convenient, cannot address the non-physical components of gender identity. And it is not just abnormalities in chromosome count that affect gender identity and assignment.

Consider, for example, persons with Androgen Insensitivity Syndrome (AIS). This condition occurs in one of every 13,000 births. It is a genetic problem that affects gender identity and assignment in a real and measurable way. In the womb, all fetuses start out as characteristically female. During fetal development, those destined to become male receive a big shot of the male hormone androgen, which in turn causes the development of male sex organs and other male characteristics.

In people with AIS the androgen doesn’t “take” in typical fashion. This may be due to a lack of androgen receptors.  To a greater or lesser extent, their developing bodies do not respond to the rush of androgen. In a substantial percentage, it scarcely affects their development at all. These people are born with all the outward signs of being female, and often are considered dramatically beautiful women. Everyone (including them) believes they are female. They are raised as female, they identify as female, and they are treated universally as female.

It is only when a genetic test is performed – usually for some other reason – that it is determined that these individuals have an XY chromosome arrangement that would normally classify them as male. By this time these individuals have spent their lives as women and are recognized as such. What should we do when we find out they are genetically male? Must they be forbidden from marrying men and forced to either marry women or remain single? What of those who are already married to men? Is their marriage automatically invalidated by the discovery that both partners in the marriage are genetic males?

Another condition, XX Male Syndrome, results in the opposite effect: a person with a karyotype of two X chromosomes who appears male. Although such persons’ chromosomal makeup is female, the manifestation of their sexual organs is male, both externally and internally. Are they to be labeled male or female based on their genetic makeup, or on their possession of penis and testicles and absence of vagina and ovaries?

There are many other possibilities in the realm of intersex gender assignment. Science makes things known, but science cannot dictate legalities or moralities. The nation of Germany (Germany!) has recently added a third option on birth certificates: female, male, or “indeterminate.” Eventually this blurring of distinction must be resolved, either by some detailed and scientifically defensible legal definition of who is a man and who is a woman, or by eliminating the old categories and defining marriage as a contract between two people, irrespective of perceived gender. And science is unlikely to arbitrate a dispute about definitions.