The Obamas and the Kennedys

5 August 2009: President Barack Obama's daughter Sasha sneaks up on him from behind the sofa in the Oval Office Photograph: Pete Souza/The White House

3 March 2009: President Obama examines the Resolute Desk with John F Kennedy's daughter, Caroline Kennedy Schlossberg Photograph: Pete Souza/The White House

10 October 1962: The Kennedy children visit the Oval Office at the White House Photograph: White House/Rex Features

1963: John Jr under his father's desk in the Oval Office. He called the spot 'my house' and was peeking out from behind the 'secret door' Photograph: Stanley Tretick/AP

14 April 2009: President Obama with his daughters, Malia and Sasha, and their dog Bo on the south lawn of the White House Photograph: Lawrence Jackson/The White House

1963: President Kennedy with his family Photograph: Claudio Edinger/Getty Images

15 August 2009: Barack Obama and his daughters choose an ice cream flavour during a visit to Yellowstone national park Photograph: Pete Souza/The White House

26 August 2009: Malia and Sasha Obama wait with their father for their lunch to arrive at a restaurant in Martha's Vineyard, Massachusetts Photograph: Jewel Samad/AFP/Getty Images

President Kennedy's family on holiday Photograph: AP

2 February 2009: President Obama relaxes in the Oval Office with his wife and daughters Photograph: Pete Souza/The White House

2 February 2009: President Obama's family join him in his private study off the Oval Office Photograph: Pete Souza/The White House

1963: President Kennedy with his son John Jr outside the White House Photograph: AP

October 1963: President Kennedy with Caroline and John Jnr in the Oval Office Photograph: Sipa Press/Rex Features

4 March 2009: Barack Obama pushes his daughters, Malia and Sasha, on a swing-set on the south lawn Photograph: Pete Souza/The White House

1 April 1961: Caroline Kennedy plays with friends on the White House lawn, watched by her mother Photograph: Joseph Scherschel/Time & Life Pictures/Getty Images