ACTIVISTS on warring sides of the abortion debate rarely take the same position when it comes to Supreme Court cases involving women’s rights. But pro-choicers and pro-lifers have found common cause in Young v United Parcel Service, a pregnancy discrimination case the justices will take up on December 3rd. Yet the ideological overlap, while intriguing, is no guarantee that justices will reach consensus.

Peggy Young was working part-time as the driver of a delivery truck for UPS when she became pregnant in 2006. Ms Young’s midwife, frowning on the requirement in her job description that she haul 70lb boxes, wrote a note to UPS recommending that “she not lift more than 20 pounds." On this basis, Ms Young requested a few months of a lightened load. Other UPS employees were eligible for such an accommodation, she reasoned, so she wasn’t asking for anything out of the ordinary. Workers who were injured on the job, who were disabled under the terms of the Americans With Disabilities Act, or who lost their driving credentials were all eligible (under the collective-bargaining agreement) for “light duty” assignments. But Carolyn Martin, the company’s occupational health manager, rejected Ms Young’s request. Since pregnancy did not fall into any of the three categories of workers eligible for alternate assignments, UPS would not switch her to a less physically onerous job. Ms Martin "empathise[d] with [Ms Young's] situation and would have loved to help her," but sent her packing on an unpaid leave.

The case concentrates on whether the Pregnancy Discrimination Act (PDA), a law passed in 1978 that fortified employment protections for pregnant women under Title VII of the Civil Rights Act, requires companies to accommodate women like Ms Young. The PDA prohibits employers from discriminating “because of” pregnancy and holds that pregnant women must not be treated