Three-quarters of the women in the U.S. workforce will become pregnant at some point. Despite both federal and state laws prohibiting employers from discriminating on the basis of pregnancy, that hasn’t stopped businesses from doing so anyway—as Peggy Young’s case against UPS demonstrates. The question before the U.S. Supreme Court on Wednesday was what, if anything, the justices were going to do about that. My guess is not much.

Young, a former delivery driver for UPS, became pregnant and requested a modification to her job assignment after her doctor told her not to lift more than 20 pounds in the first 20 weeks of her pregnancy. UPS denied her request, citing their “pregnancy-blind” policy that refused workplace accommodations like light-duty assignments to any employee unless they were injured on the job, qualified as disabled under the Americans With Disabilities Act, or lost their federal driver’s certificate. Because Young’s circumstance did not fit into any of those categories, she was instead forced to take unpaid leave, which meant a loss of her health insurance during her pregnancy and delivery. Young returned to work after the birth of her baby and sued UPS for pregnancy discrimination under the 1978 Pregnancy Discrimination Act (PDA).

Congress passed the PDA to amend another anti-employment discrimination law, Title VII of the Civil Rights Act, and in response to a 1976 Supreme Court decision that ruled pregnancy discrimination is not a form of sex discrimination. The PDA requires that employers treat “women affected by pregnancy” the same as “other persons not so affected but similar in their ability or inability to work.” It sounds simple enough—employers cannot carve pregnancy out as a separate condition to evaluate employee accommodation requests. But leave it to the federal courts and corporate America to muck that all up.

Young and her attorneys argued in lower court hearings that because UPS granted light-duty job assignments to workers who were “similar” to Young in their “inability” to perform all job functions—in other words, UPS accommodated workers with physical limitations other than pregnancy—it violated the PDA by refusing to grant the same to her. But Young lost at both the trial court and the Fourth Circuit Court of Appeals, which ruled that because UPS’s policy was “pregnancy-blind” and didn’t specifically state a bias against pregnant workers, it wasn’t discriminatory. Also, the Fourth Circuit reasoned that Young actually wasn’t “similar” to any of those three categories of workers UPS’s policy accommodated. Therefore, it ruled, she wasn’t entitled to be treated the same way they were.

The Supreme Court justices wrestled with this question Wednesday: Just how poorly are employers allowed to treat pregnant workers?

True to form, Justice Antonin Scalia argued that Peggy Young and other advocates were seeking a “most-favored nation treatment”—referring to the term used in international trade to denote a high status—for pregnant employees by requiring employers to make accommodations for them they wouldn’t have to make for other employees. Thankfully Justice Ruth Bader Ginsburg, back on the bench following emergency heart surgery, was there to respond that UPS’s policy would leave pregnant workers with the “least-favored nation” status.

In addition to comparing pregnant workers to most- or least-favored nations, based on whether an employer should be required to honor workplace accommodation requests like additional bathroom breaks, the ability to sit on a stool while cashiering, or permission to carry a water bottle on the job, it was clear the idea of making employers adjust to the needs of pregnant workers remained a controversial one among the justices.

Leading the charge on the concern-trolling for the rights of employers was Justice Samuel Alito, who peppered Young’s attorney, University of Michigan law professor Samuel Bagenstos, with hypotheticals to test just how far an employer’s accommodations would have to reach. Alito offered the example of two categories of workers with lifting requirements. One category consisted of people who work alone and lift all the time, while the second included workers who lift occasionally and do it where there always are many others in the same class available to do the lifting—so those who have help, essentially. If an employer accommodates the workers in the second category, asked Alito, must it also accommodate workers in the first? No, Bagenstos said, because the law’s text prohibits discrimination “based on the source of the disabling condition. It doesn’t prohibit discrimination based on different job classifications,” and the problem with UPS’s and other pregnancy-blind policies is they do just that.

But if the justices were concerned that requiring employers to allow pregnant employees additional bathroom breaks would open the floodgates for mandates on employers, they also appeared reluctant to simply take UPS at its word that its policy was not discriminatory. Leading the charge in scrutinizing UPS’s case was Justice Elena Kagan. “What we know about the PDA is that it was supposed to be about removing stereotypes of pregnant women as marginal workers,” Kagan said to UPS’s attorney, Caitlin Halligan. “It was supposed to be about ensuring that they wouldn’t be unfairly excluded from the workplace. And what you are saying is that there’s a policy that accommodates some workers, but puts all pregnant women on one side of the line.”

It’s worth noting that UPS recently changed its policy and has said it will begin offering pregnant employees light-duty accommodations in January; it also just settled a case nearly identical to Young’s. In that case, Julie Desantis-Mayer, a UPS delivery driver alleged that she was forced onto unpaid leave and lost her health insurance in 2012, just before the birth of her baby.

In 2012, the Equal Employment Opportunity Commission (EEOC)—the federal agency responsible for monitoring and enforcing federal employment laws like the PDA—received nearly 4,000 claims of workplace pregnancy discrimination. It’s safe to say that if the EEOC received 4,000 pregnancy discrimination complaints, more instances of workplace discrimination are going unreported. As Bryce Covert, economic policy editor at ThinkProgress, reported, it’s estimated that more than a quarter-million women are denied requests for a workplace medical accommodation for their pregnancies. In fact, the economic impact of policies like the one UPS defended to the Roberts Court that refuse to accommodate pregnant workers is so great that at least nine states have stepped in to pass legislation like the Pregnant Workers Fairness Act. This act requires all employers to give pregnant workers reasonable accommodations unless those accommodations would impose an undue hardship on the employer. According to UPS in its brief to the Roberts Court, those state-level policy changes are partly responsible for its decision to stop refusing workplace pregnancy accommodations, stating in its brief that the new policy “will aid operational consistency given that a number of States in which UPS operates have relatively recently mandated pregnancy accommodations.”

So while UPS and other employers like Wal-Mart have changed their practices and now accommodate requests in line with state-level Pregnant Workers Fairness Acts, which were passed to remedy the economic impact of employers forcing pregnant workers off the job, UPS still argued to the Roberts Court that the PDA does not require the policy change.

In other words, UPS went before the Supreme Court and fought for the rights of employers to kick pregnant workers off the job, and for at least an hour the justices gave this argument very serious consideration.

At the close of arguments, it was not clear how the Roberts Court would resolve the problem of workplace discrimination against pregnant employees, or if it would try at all. The Court has a lot of options before it, including sending the case back to the lower court for a full trial to develop a record of just what categories of employees pregnant workers should be compared to when evaluating accommodation requests, what burdens, if any, employers face in granting these requests, and so on. It also has the option of ruling in favor of UPS and of holding that states are free to more generously protect the rights of pregnant workers than the federal law at issue in Young.

But even if it’s not clear how the votes on the bench line up, Young’s attorney closed by making sure the justices at least heard what’s at stake one last time: “You have to treat pregnant workers as just as valued employees as anybody else, and if you think it’s valuable to keep these employees on the job who are injured on the job because they keep valuable … knowledge within the company, do that for pregnant women,” Bagenstos said.

Let’s see if the Roberts Court agrees.