The law was enacted in part to alleviate people’s fears that their genetic information could be used against them. There were concerns that people who feared discrimination if they got a genetic test would refuse to participate in clinical trials needed for the advance of medical science, or avoid getting tests that might be useful for their health.

There have been very few cases under the law, and legal experts said they did not know of any others that had gone to trial. The cases so far have mostly involved workers suing employers who had asked for their medical histories. A Connecticut woman claimed she was fired after she disclosed that she had a gene that predisposed her to breast cancer. Her claim was settled out of court with a nondisclosure agreement.

Sharon Terry, chief executive of the Genetic Alliance, an advocacy group for people with genetic disorders that lobbied for the law, said she and other advocates were pleased by the outcome of the case in the Atlanta court, but surprised by both its substance and the dearth of other cases.

“Is the law so effective that employers are well-informed and not going there, or is this less of an issue than we thought it would be?” Ms. Terry said, adding that she thought there was some truth in both.

The case of the warehouse workers began more than two years ago when Atlas asked its loss prevention manager, Don Hill, to find out who was defecating in one of its warehouses where grocery store goods were stored. After looking at employee work schedules, Mr. Hill identified workers who he thought were present when the deeds were done. He asked a forensics lab to compare the DNA of men the company suspected with the DNA of the feces to see if there was a match.

Everyone knew about the problem, Mr. Lowe said. The workers were abuzz, wondering what sort of person could be doing it. Then, one day after his break, Mr. Lowe was ushered into a room by his supervisor. His union steward, a human resources manager and Mr. Hill were waiting for him.

“They sat me down and asked me did I know why I was asked to come upstairs,” Mr. Lowe said. “They asked if I knew about the feces. I said I had heard about it and thought it was gross. They asked me to take a DNA test because they had reason to believe it was me.”