A woman who claims Backpage.com allowed her to be sold for sex as a minor will be able to sue the website despite arguments that federal law and recent precedent should bar her case, according to a Massachusetts federal judge.The 18-year-old woman, who says she was sold for sex “in Massachusetts and Florida through various means, including Backpage.com,” can continue her suit against the company because she alleged that it changed the content of an ad she was listed in — a claim that, if true, could render the website vulnerable.