By MICHAEL KIMMEL

MOST everyone knows by now about “lookism” — the preferential treatment given to those who conform to social standards of beauty. Research suggests that people who are judged physically attractive are seen as more competent and more socially graceful than those who aren’t; they have more friends and more sex; and they make more money. One economic study found a 5 percent bonus for being in the top third in the looks department (as assessed by a set of observers), and a 7 to 9 percent penalty for being in the bottom 9 percent.

All of which might come as a surprise to Melissa Nelson, a 33-year-old dental assistant in Fort Dodge, Iowa. Ms. Nelson, you see, was fired in 2010 by her dentist boss, James Knight, because she was too attractive. Mr. Knight, who is married, said he felt that Ms. Nelson’s beauty was simply too tempting to pass unnoticed and that he was worried he would have an affair with her. And so as a pre-emptive move (and at his wife’s insistence), he fired her.

Ms. Nelson sued on grounds of sex discrimination. Stunningly, an Iowa district court dismissed the case, contending that she was fired “not because of her gender but because she was a threat to the marriage of Dr. Knight.” Naturally, she appealed, but last week the Iowa Supreme Court upheld the lower court’s decision (for the second time), maintaining its view that an employee “may be lawfully terminated simply because the boss views the employee as an irresistible attraction.”

Now, you might think that this case of reverse-lookism gives the gorgeous a taste of their own medicine. Better than being fired because you’re ugly, right?

But I propose that we think not about how such a case differs from its converse, but about how they are actually similar.

Discrimination based on beauty is rooted in the same sexist principle as discrimination against the ugly. Both rest on the power of the male gaze — the fact that men’s estimation of beauty is the defining feature of the category.

I know you might think: “Not so fast. What about good-looking or ugly men?” And yes, handsome men reap the benefits of lookism and the short, fat and bald suffer its penalties. Lookism is gender-neutral.

The workplace, however, isn’t. Think of all those mannequin-thin sales representatives for pharmaceutical companies, whose job is to persuade physicians, a great many of them men, to prescribe their products. Think of companies like American Apparel, whose top executive, Dov Charney, has been accused of firing employees that he judges unattractive. The writer Naomi Wolf has called this the “professional beauty quotient” — a standard of beauty that tacitly operates as an occupational qualification (as flight attendants have complained). The glass ceiling is reinforced by a looking glass.

But the professional beauty quotient has now morphed into what we might call the Goldilocks dilemma. Like the porridge in that famous fable, you can’t be too cold. But as Ms. Nelson found out, you can’t be too hot, either. You have to be “just right.” But just right in whose eyes? Beauty may be in the eye of the beholder, but the beholder in the workplace usually has a Y chromosome.

After all, the case of Melissa Nelson rests not on her beauty but on Mr. Knight’s perception of her beauty. In his eyes, her beauty was simply too tempting, too potentially injurious. (Ever notice, the writer Timothy Beneke once asked, how the words we use to describe women’s beauty — bombshell, knockout, stunning, femme fatale — are words that connote violence and injury to men?)

What a pathetic commentary on Mr. Knight: his willpower so limp, his commitment to his wife so weak, that he must be shielded from the hot and the beautiful.

Now, I ask you: Where have we heard that before — that men’s vulnerability to women’s sexuality and attractiveness is so great that women must be prevented from showing any part of their bodies to them?

Yes, like some Midwestern Taliban tribunal, the Iowa Supreme Court permitted a male boss to fire anyone who might conceivably tempt him. Mullah Omar would approve.

Maybe we ought to reconsider the case of Samantha Elauf, a Muslim teenager from Oklahoma, on whose behalf the Equal Employment Opportunity Commission sued Abercrombie & Fitch in 2009 after she was not hired because her hijab did not meet the retailer’s appearance policy. Maybe instead, the Iowa Supreme Court should require all beautiful women to wear burqas. With Ms. Nelson completely covered, Mr. Knight could pay full attention to his patients’ dental concerns — while ignoring the ethical cavity that mars discrimination law in Iowa.

Michael Kimmel, a professor of sociology and gender studies at Stony Brook University, is the author of the forthcoming book “Angry White Men: American Masculinity at the End of an Era.”