Jag tror att det är Metusalehs barn av Robert Heinlein, även om det också skulle kunna tänkas var Tillsammans för kärlek som använder samma bakgrund.
The Howard Families derive from Ira Howard, who became rich in the California Gold Rush, but died young and childless. The trustees of his will carried out his wishes to prolong human life by financially rewarding those with long-lived grandparents, who married each other and had children. By the 22nd Century, these families have a life expectancy of 150 years, and have kept their existence secret, but reveal themselves to the society established under The Covenant, which refuses to believe that the Howard Families obtained their lifespan by selective breeding, instead insisting they have developed a secret method to extend life. Though the Administrator of the planet, Slayton Ford, is convinced the Families are telling the truth, he cannot prevent efforts to force the Howard Families to reveal their (non-existent) rejuvenatory abilities.
Att citera från texten:
Mary got out, said hello to the guards and went on through a tunnel into a large underground room where fifty or sixty men and women were seated. She chatted until a clock announced midnight, then she mounted a rostrum and faced them.
"I am," she stated, "one hundred and eighty-three years old. Is there anyone here who is older?"
No one spoke. After a decent wait she went on, "Then in accordance with our customs I declare this meeting opened. Will you choose a moderator?"