The son was identified as Adam Paul Laxalt, now a lawyer in Nevada, in the statement given to the Albuquerque (N.M.) Journal by Domenici, now 80, who served six terms in the Senate, and the son's mother, Michelle Laxalt of Alexandria, Va., the newspaper said.
Michelle Laxalt is the daughter of Paul Laxalt, who represented Nevada in the Senate and also was his state's governor.
Domenici said he had pledged not to reveal his son's parenthood, but indicated he was disclosing the matter because he anticipated another, unnamed source was about to make the story public.
"Rather than have others breach this privacy, I have decided to make this statement. The circumstances now compel me to reveal this situation," he said, adding his family "has been aware of these events for several months."