 Story highlights A court will study a paternity lawsuit brought against the former King of Spain 
 
 A woman from Belgium alleges Juan Carlos had a relationship with her mother 
 
 Madrid (CNN) Spain's former King Juan Carlos, 77, will face a paternity lawsuit -- by a Belgian woman alleging that he's her father -- before the nation's Supreme Court, a 12-judge panel ruled Wednesday. Ingrid Sartiau says her mother had an affair with him in the 1960s, while he was married and a crown prince. Royal officials said they respected the independence of the court, but refused further comment. While the court agreed to take Sartiau's claim for study, it rejected a separate paternity suit against the former King brought by a Spanish man. Sartiau alleges that her mother and the married Juan Carlos had a relationship in late 1965, and she was born, as a result, in August 1966, said her attorney, Jaume Pararols. The plaintiff has asked the court to require a DNA test for the former King, who has 20 days to make an initial response to the lawsuit. He stepped down last June to make way for his son, Felipe VI, saying it was time for a "new era". Juan Carlos no longer has immunity from prosecution, but he has protection that permits cases against him to be heard only by the Supreme Court, which is Spain's second highest, after the Constitutional Court.
– Being an ex-king has its drawbacks, Spain's Juan Carlos has discovered. He enjoyed immunity from prosecution during his 39 years on the throne, but since he handed the crown to his son Felipe last year, two paternity suits have made it into the courts. One from a Spanish man was rejected, but the country's Supreme Court has agreed to hear a case from a 48-year-old Belgian woman who says the former king is her father, reports the BBC. Ingrid Sartiau claims that she is the product of an affair Juan Carlos had with her mother in 1965, when he was married but still a crown prince. Her lawyer tells CNN that Sartiau's mother is still alive and is willing to testify. "We would like to reach a settlement. My client never wanted it to get to this point," he says. The 77-year-old ex-king now has 20 days to respond to the lawsuit, and the court could require a DNA test from him.