Reproduction and Gender

Note: This is the second post in a series interrogating the claim that gender is best understood as a binary phenomenon. The first one is Chromosomes and Gender; you might want to start there.

In the first post of this series, we established that chromosomal configurations are insufficient to serve as the basis for an unambiguous, binary definition of “biological sex”. However, the proponents of these models may still be able to point us in interesting directions:

Even when abnormalities occur in chromosomes, they still comprise some combination of Xs and Ys. The reproductive possibilities for intersex persons seems to align with the chromosomes. Male reproductive capacity comes only from those who have Y chromosomes. Female reproductive capacity comes only from those who have no Y chromosome. Is this not reflective of the dimorphic paradigm of Scripture?

Although we didn’t explore it in the last post, Burk’s preference for a chromosomal model of biological sex is grounded in an appeal to “reproductive capacity”. This is a concept that bears further exploration.

But what do we even mean by “reproductive capacity”? One approach to finding a definition might be to first break human reproduction into its requisite components and work from there. A modern list might look like this:

1. A sperm cell
2. An egg cell
3. A hospitable environment in which both the sperm and egg can survive
4. An opportunity for those two cells to encounter each other
5. Merging of both of those two cells to form an zygote
6. A hospitable environment for the fetal development to continue for about nine months

While this division is somewhat crude, it does suggest a couple of noteworthy observations:

First, although the knowledge of sperm and eggs is far older than knowledge of chromosomes, neither had been observed until the late 17^th century, and it was another 150 years until their roles were articulated in a way that approximates our modern understanding.² Prior to these discoveries, there were many competing theories, some of which are even implicitly affirmed by the Biblical writers, such as when the author of Hebrews includes this note in his argument for the superiority of Melchizedek over Levi:

9 One might even say that Levi himself, who receives tithes, paid tithes through Abraham, 10 for he was still in the loins of his ancestor when Melchizedek met him.

Some might argue that the writer is speaking metaphorically, and that what they really mean is that Levi’s eventual inheritance was reduced as a result of the tithe—or something to that effect. In any case, they say, the writer couldn’t possibly have believed that Abraham’s great-grandchildren were actually present within him when he met Melchizedek.

But why not? A survey of alternatives to “egg theory” shows a wide variety of beliefs that sound quite outlandish to our modern ears. Our own difficulty in taking this reproductive model seriously is not evidence that the writer did not genuinely believe it—this is far from the wildest model that has been seriously entertained. And even if the writer did intend to be read metaphorically, what other model would they have claimed as the “real” one? There is no evidence that anyone in the ancient world had a model that even remotely resembles our modern understanding of reproduction.

The difference between ancient and modern models of reproduction has significant implications for any attempt to assign sex based on reproductive capacity. Use of our modern models runs a significant risk of making assignments that would have been incomprehensible to the original audiences to the Bible was written, while our knowledge of—and consensus regarding—ancient models is insufficient to address the ambiguities that modern biology has brought to light. Given complementarians’ stated goals of eliminating ambiguity and preserving a Biblical model of gender, neither alternative seems acceptable.

The second observation about our list is that even when we abandon the requirement to maintain consistency with ancient worldviews, we find that technology is increasingly able to assist or replace many components of the reproductive process. Surgical sperm harvesting and IVF provide a way for eggs to be fertilized without any sexual activity—and those embryos can be brought to term by individuals with no relation to either of the biological parents. Uterus transplants have been successfully used to allow people born without them to carry children to term.³ Artificial wombs have been used to provide for the needs of late-term sheep fetuses, with human applications more a question of “when” rather than “if”.⁴

Each of these techniques was developed in response some group of people lacking these capacities, so while they are important parts of “reproductive capacity”, none of these components can be used to unambiguously label every person as either “male” or “female”.

The only items in the list that for which we don’t have technological interventions are the production of sperm and eggs themselves, which is the function of the testes and ovaries, respectively. Can these organs be used to unambiguously assign sex?

In a word: no. While most people are born with either testes or ovaries—that usually work—some people are born with neither, and some 46,XX/46,XY individuals have both! We’ve landed at another irreconcilable dilemma.

It would seem that our exploration of reproductive capacity has failed to produce any criteria for assigning gender that are sufficient for the needs of complementarians. Ancient models provide no resolution to the ambiguities that we find in nature; modern models do no better and have the additional disadvantage of being impracticable for ancient people.

Our list of candidates for the source of “biological sex” is dwindling:

• Chromosomes
• Secondary sex characteristics
• Hormone levels
• Gonads (internal reproductive organs)
• Genital configuration
• Gender identity (at least insofar as it has been linked to brain structures)

The remaining areas will have to wait for a future post.

Looking for the rest of the series?

1. Chromosomes and Gender
2. Reproduction and Gender
3. External Sex Characteristics and Gender
4. …Coming eventually