I’ve been thinking about shatnez recently. That’s the Torah’s inexplicable prohibition against wearing fabric containing a mixture of wool and linen. I say “inexplicable” because neither Leviticus nor Deuteronomy, the two books that mention this rule, explain why we’re supposed to follow it. That makes shatnez a chok, a law given without a reason (as opposed to a mishpat, a law whose reason is explained). It’s the theological equivalent of “Because I’m the mommy, that’s why!”The reason shatnez seems resonant to me right now is that I have a kid whose laws governing clothing are as strict as the Torah’s. She won’t wear anything made of wool, denim, khaki, or corduroy. She abhors anything with tight sleeves or a tag in the back. She cannot abide shoulder straps with any lace, appliqués, or detailing that might touch her shoulders. She smites (metaphorically) all halter-tops and any sundress that ties behind the neck. She disdains the narrow crewneck, the turtleneck, the elasticized sleeve, the wide waistband.But Maxie’s laws are mishpatim, not chukim. Her reasoning is known. She has sensory issues, and all those sartorial items feel horrible to her.I understand her logic, but what’s the Torah’s? Maimonides theorized that it had to do with pagan priests who wore robes made of a wool-and-linen combo. Heaven forbid anyone confuse us with those guys. Another explanation is that shatnez hearkens back to the offerings Cain and Abel brought to God. One brought flax (the source of linen) and the other brought a sheep (the source of wool), and look how well their story came out. So, uh, let’s not do that.According to the scholarly Jewish textual resource known as Wikipedia, some people believe that shatnez was based on scientific reasoning. Wool shrinks when it gets wet, and linen doesn’t, so if the fibers were combined it might lead to perspiration and other hygiene issues (I’m unclear on this part). And we Jews are all about the hygiene. Which is why we all have asthma and neuroses today.Even the derivation of the word shatnez is unclear. One theory holds that it’s a mash-up of three words: shua, which refers to combing raw fiber; tuvi, the process of spinning fiber into thread; and nuz, the weaving of thread into cloth. The Zohar, Madonna’s favorite kabbalistic text, says that shatnez comes from two words: “Satan az,” or “Satan is strong.” Do not mess with Satan by bringing together products that should not go together.In the Coptic language, spoken in ancient Egypt until the 7th century or so and somewhat similar to Hebrew, shatnez sounds an awful lot like sasht nouz, meaning false weave. A Greek version of the Torah from the era of Alexander the Great translates shatnez as false or adulterated.For a little clarity (OK, any clarity) on the subject, I checked in with Amy Kalmanofsky, assistant professor of Bible at the Jewish Theological Seminary. “No one entirely knows why we have shatnez,” she said, “but it’s obviously related to purity being the ideal. The world is created in order, and order reflects the divine will and the divine universe. Mixtures are chaotic—they introduce unholiness in some way. But the interesting thing is that the high priests wore shatnez, and the curtain in the mishkan, the Tabernacle, was made with wool and linen. In those cases you could say that shatnez was the opposite of unholy; it was indicative of holiness. Only the sanctified people and spaces are holy enough to be draped in it.” In ancient times and today—aren’t the sacred and the profane often awfully close together?Kalmanofsky mentioned the 1966 book Purity and Danger, by Mary Douglas. It’s a seminal work in social anthropology, looking at the interplay of the sacred, the clean, and the unclean in different cultures. Douglas wrote that the laws of kashrut are about maintaining symbolic boundaries, and the foods that are prohibited are the ones that don’t seem to fall clearly into any category. (Lobsters? Sea insects! Pigs? Why won’t you chew your cud, you cloven-hoofed freaks!) Similarly, shatnez may be just another way to guard the boundaries of purity.This being America, you can hire people to guard these boundaries for you and shatnez-check your wardrobe. Visit the Shatnez Testers of America web site for more info—you’ll find shatnez alerts (tragic news: Barneys New York’s suits are shatnezville), guidelines for what items need to be checked (the halachic jury is still out on baseball gloves), lists of shatnez-testing laboratories in various countries. Shatnez checkers with special Good Housekeeping Seals of Shatnez can take samples from fabric (apparently without damaging the garment) to send to the shatnez lab, where they’re examined under low-powered microscopes to identify the fibers. Some shatnez-laden clothing can be de-shatnified for a small fee.But while you can control the shatnez in your wardrobe, you’ll find it’s a lot harder to control your kids’ innate temperament and predilections. No one knows why some kids have sensory processing mishegas. Some people think it’s a construct, not a real thing. You know, like religion.And as with religion, when it comes to Maxie, I’ve decided to simply obey her laws. Her big sister’s vile, impure clothes are boxed up and put into storage for my little niece. I buy Maxie loose cotton dresses and leggings, mostly from (tagless) Hanna Andersson and Old Navy. I just discovered a new line of clothing designed by a Brooklyn special-education teacher and fashion lover (with help from her pals, a designer for Calvin Klein and a former designer for Michael Kors and Isaac Mizrahi), aimed at kids with sensory and tactile processing sensitivity. Everything’s made of super-soft cotton, with flat seams, loose collars, veggie-ink-printed labels, and a roomy fit.Maxie has rules, and I love her, so I deal. And I hope that by dealing, I can keep some of her pain at bay. Shatnez, too, is about keeping chaos at bay. And of course, you never really can. But we all have different levels of tolerance for disorder, and we all have to find our own way in the world.Marjorie Ingall is a columnist for Tablet Magazine, and author of Mamaleh Knows Best: What Jewish Mothers Do to Raise Successful, Creative, Empathetic, Independent Children.