to certain Christians, the fact that the Bible states "male and female
created He them" means that God only recognizes two genders, those
assigned at birth. To be trans or nonbinary is unacceptable, and
intersex status a tragic birth defect that must be corrected.
Of course, the Bible also says "the Lord makes poor and rich." This binary of rich and poor appears multiple times in biblical language. Do conservative Christians therefore say it is an abomination to be middle class?
Or consider the verse, "He will bless his loyal followers, both young and old." You'll find this binary of young and old many times. Yet there is no Christian movement to declare that people cannot be known as middle-aged, but must either be designated as old or as young.
The phrase "male and female created He them" comes from the book of Genesis, in what Christians call the Old Testament and Jews call the Torah. Christianity started as a Jewish sect, reading Jewish Torah scrolls, and practicing Jewish religious traditions. Many of these traditions were relinquished fairly early in Christianity, such as the requirement of circumcision. By 300 years in, kosher dietary laws had been abandoned.
But many other Jewish traditions lasted much longer. One of these was recognition of intersex babies. Under the Jewish religious rules of halacha, babies were not just classified as male or female, but under a four-sex system that also designated babies androgyne (both) or tumtum (neither). People born androgyne were to perform the religious duties assigned to both men and women; people born tumtum were not required to practice either set of duties. Jewish tradition also recognized additional categories for those whose gender status changed, due to intersex characteristics manifesting at puberty, or to never experiencing puberty at all, or to human intervention such as surgery--all categories later Christians would lump together as "eunuchs."
For many centuries, Christians recognized androgynes, tumtums, and eunuchs as well as men and women. The Church canonized saints with these designations. It was not until the Middle Ages that the novel idea arose that the phrase "male and female created He them" was not a poetic dyad, but a limitation the Church should implement in categorizing human beings. And the courts immediately started dealing with a stream of cases involving people assigned to one binary sex at birth, but living as the other, or living in their birth-assigned sexes but having intersex bodies that they or the community felt was more like the sex to which they were not originally assigned.
This shift from accepting sex and gender diversity to squashing it into a binary was awkward from the very first. And violent, too: some intersex people were burned at the stake, like witches. The categories of witch, intersex person, and gender-transgressor were often conflated. It was a ugly time in history--witness the Inquisition--in which all sorts of people who deviated from norms were tortured and burned alive in the name of God.
Today, Christians are not in the witch-burning business. That period of history is viewed as one of superstition and terrible persecution. Yet some conservative Christians continue to revile people who are gender expansive, deem gender transition illegitimate, and demand that intersex babies receive forced genital reconstruction. They claim they must impose an eternal binary, for the Bible tells them so.
But there's no need for that. The phrase "male and female created He them" is a poetic dyad, just like the phrases "rich and poor" or "old and young."
Persecuting the socially marginal is the exact opposite of what Jesus called on Christians to do. Justifying such persecution by referencing a snippet of poetic Biblical language is not just nonsense. It is a great moral wrong