No, this is not some futuristic movie like "The Children of Men" - this is a very real part of our modern culture.
The NY Times reports:
As one of the hundreds of age-restricted communities nationwide, the rules are clear on one thing: no one, absolutely no one, who is a teenager, an adolescent, a toddler, a newborn, any form of child, may call Sun City home. “Visits are O.K. as long as they’re limited,” said Mr. Szentmiklosi, who describes himself as a doting grandfather and insists that he does not have an anti-child bone in his body. “You can have children visit for 90 days per year. That means if you have 10 grandchildren, each one can visit, but they can only stay nine days each.”[Hat tip: Greg Laughlin]