The denial of a petition for a DNA sample from the body of the late Mexican music icon Juan Gabriel in Los Angeles Superior Court last week was a clear-cut victory for Ivan and Simona Aguilera, the singer's son—and lone heir to his estate—and his daughter-in-law.

And it was a serious blow to Joao Aguilera, who had hoped to legally validate his claim that the late singer was his father, which would in theory support a claim that he was entitled to a share of the estate of Gabriel, estimated by some at more than $50 million.

Without a blood sample from the singer (whose real name was Alfredo Aguilera) to compare with his own, Joao's hopes for prevailing in an Aug. 31 paternity hearing are essentially finished. Ivan and Simona Aguilera's attorneys, Gabriella A. Vidal and Anita P. Wu of Loeb & Loeb, told Judge Brenda Penny that they plan to file a dispositive motion on Wednesday, which would pre-empt that hearing.