A federal judge in Boston has handed a partial defeat to classifieds site Backpage in a lawsuit brought by three teens who alleged that the site facilitated sex trafficking.

U.S. District Court Judge Leo Sorokin ruled that one of the victims can proceed with her claims against the company, but dismissed claims by the other two teens. The victim who can proceed alleged that Backpage reworded an ad about her to suggest that was an adult, when she was actually only 15.

Sorokin’s ruling stems from a lawsuit filed last year on behalf of three teen victims. They alleged that Backpage “intentionally facilitated” sex trafficking by editing ads on the site to make it appear as if minors were actually adults.

Backpage asked Sorokin to dismiss the complaint, arguing that Section 230 of the Communications Decency Act immunizes Backpage from civil lawsuits based on material posted by users.

Sorokin said in a ruling issued Thursday that the Communications Decency Act required dismissal of claims brought by two of the teens. “The complaint is devoid of factual allegations plausibly supporting the contention that Backpage created content, expressly or impliedly, as to either of these two plaintiffs,” he wrote.

He added that sites don’t lose their immunity under the Communications Decency Act merely by editing ads.

But Sorokin said the evidence showed that an ad for the third teen “was changed between submission and publication.”

That revision was significant enough to warrant further proceedings, the judge ruled.

Backpage has faced numerous lawsuits alleging that its “adult” ad section — which contains obvious prostitution ads — facilitates sex trafficking. The company has prevailed in several prior cases, including a previous suit brought in Boston, on the ground that the Communications Decency Act immunizes Backpage from civil lawsuits based on material posted by users.

Faced with growing criticism, including by lawmakers in the U.S. Senate, Backpage shuttered its adult ads section last year. Since then, however, many prostitution ads appeared to simply migrate to other sections of the site.

This month, concern over Backpage’s practices spurred federal lawmakers to pass the Fight Online Sex Trafficking Act (H.R. 1865), which weakens the Communications Decency Act. The new bill, which was passed last week but has yet to be signed by President Trump, allows victims to sue websites that knowingly facilitate sex trafficking and allows state prosecutors to bring criminal charges against the operators of websites that facilitate prostitution. (The Communications Decency Act has always allowed federal prosecutors to bring criminal charges against operators of sites that facilitate crime.)

Many digital rights advocates and other industry observers oppose the Fight Online Sex Trafficking Act, arguing that it will result in censorship of legitimate speech. The Electronic Frontier Foundation warned the Senate last year that the law “would create an incredibly strong incentive for intermediaries to err on the side of caution and take down any speech that is flagged to them as potentially relating to trafficking.”

Santa Clara University law professor Eric Goldman, who testified against the new law at a Senate hearing, notes that Sorokin’s recent ruling shows that the Communications Decency Act never provided Backpage or other sites with “absolute immunity.

“Section 230 has been demonized as protecting Backpage, and that fundamental assumption appears to be flawed,” Goldman says.

He adds that opponents of the new law had unsuccessfully urged lawmakers to wait for Sorokin’s ruling before deciding whether it was necessary to revise the Communications Decency Act.

“This ruling should influence Congress’s decision making,” he says. “We told Congress it was coming, and they rushed ahead without waiting.”