Undeniable

From Publishers Weekly : "In Grace's fast-paced sixth thriller featuring former Navy SEAL Nolan Kilkenny (after 2007's The Secret Cardinal ), Nolan is about to donate a piece of his liver to Zeke Oakley, a two-year-old adopted boy whose parentage is unknown, when a doctor informs him that genetic testing shows that Nolan's father, Sean Kilkenny, the newly appointed U.S. ambassador to the Vatican, is also Zeke's father. After Sean denies this, Nolan sets out to discover how …