The Original Cousins

The lyrics:

Meet Cathy, who's lived most everywhere,
From Zanzibar to Barclay Square.
But Patty's only seen the sights
A girl can see from Brooklyn Heights --
What a crazy pair!
But they're cousins,
Identical cousins all the way.
One pair of matching bookends,
Different as night and day.
Where Cathy adores a minuet,
The Ballet Russes, and crepe suzette,
Our Patty loves to rock and roll,
A hot dog makes her lose control --
What a wild duet!
Still, they're cousins,
Identical cousins and you'll find,
They laugh alike, they walk alike,
At times they even talk alike --
You can lose your mind,
When cousins are two of a kind

from wikipedia,about the show:

from 1959-1963. First aired 9/18/59. The Patty Duke Show was, atypically for the time, filmed in New York and not in Hollywood. This was done because Duke was only 15 when the series began, and California's strict child labor laws curtailed the number of hours that child actors could work. New York, by contrast, did not have such stringent laws, thus allowing producers to devote more time to the production—a distinct advantage, since Duke effectively carried the show. Duke was to turn 18 during the 1965-66 television season; consequently ABC wanted to shift the show's production to Hollywood. To the network's displeasure, Duke was reluctant to make the move; at the time, she was in the midst of breaking off her relationship with her managers, who were insisting upon the move. Nonetheless, a few of the last shows were in fact filmed on the West Coast.
The show's theme song, which has since been parodied many times over in pop culture, illustrates the two girls' differences: Cathy adores the minuet, the Ballet Russe, and crêpes Suzette, while "Patty loves to rock 'n' roll; a hot dog makes her lose control."