“A woman may not don man’s apparel,” commands the book of Deuteronomy, “nor shall a man don woman’s clothing; for whoever does these things is abhorrent to the Lord your God.” As Moshe Kurtz explains, talmudic scholars have debated the reasons for, and applications of, these prohibitions—known in rabbinic scholarship by the Hebrew phrase lo yilbash (he shall not don). To an extent unusual in Jewish law, most rabbis agree that what constitutes male or female dress changes over time and should be determined by societal norms. Yet, Kurtz argues, such flexibility does not imply that the tradition views sex differences themselves as infinitely malleable:
While at one juncture it was exclusively masculine to wear pants, today it is not so. . . . Nonetheless, it is imperative, [according to the rabbinic consensus], to maintain proactively some form of gender marker.
The imperative to maintain the integrity of gender norms remains more relevant today than ever, and it should encourage us to err on the side of caution in our observance of this halakhah. While the details and applications of lo yilbash are debatable, the ethos is undeniable.
Midrash Tanḥuma, [an ancient homiletical work], relates that when [the Roman proconsul] Turnus Rufus challenged Rabbi Akiva as to why God did not create baby boys pre-circumcised, the latter replied that “God gave the mitzvot to the Jewish people in order to refine them,” meaning that God wished to partner with humankind in the endeavor of perfecting His creation. One must be careful not to uproot God’s will from our world, but rather to accept His sacred charge to . . . enhance and build upon the foundation that He has created.
A critique of Kurtz’s argument, although not of his broader conclusions, can be found here.