BOSTON - A federal judge in Massachusetts has ruled that Bill Cosby's wife must answer questions under oath in a defamation lawsuit filed by seven women who claim Cosby sexually assaulted them decades ago.

A lawyer for the women has sought to compel Camille Cosby to give a deposition in the lawsuit. Last month, a magistrate judge rejected Cosby's bid to quash the deposition subpoena.

On Thursday, U.S. District Judge Mark Mastroianni upheld the magistrate's ruling but said she may refuse to answer questions that call for testimony prohibited by the Massachusetts marital disqualification rule. The rule generally prohibits spouses from testifying about private conversations with their spouse.

The women's lawyer hoped to depose Camille Cosby this month, but it was not immediately clear when the deposition would be taken.