Before they even knew what the White House was... this is baby Barack with his mother, anthropologist Ann Dunham, in Hawaii, and baby Mitt in the arms of father George Romney, who went on to become head of American Motors and governor of Michigan (left pic AP)

It doesn't get more American than this. A young Obama swings a baseball bat in Hawaii, while six-year-old Romney gets ready to hit one out of the park in Detroit (right pic AP)

Obama was named after his father, an economist from Kenya, but his father was mostly absent from his life. Here they are together in a rare visit by Obama Snr to Hawaii. Romney was close to his father - pictured here at New York's World Fair soon after George Romney became governor of Michigan (both pics AP)

After studying law at Harvard, Obama met Michelle Robinson at a law firm in Chicago. Romney and Ann Davies knew each other from school days. She converted to the Mormon Church, and they wrote regularly to each other while Romney was away in France for more than two years as a missionary

Soon after his return, Romney and Ann married. They were both students at the time. Obama and Michelle married in Chicago in 1992

Obama worked at the University of Chicago Law School, and in 1992 took part in a voter registration drive in Illinois. Romney worked as a management consultant and helped to found the private equity company, Bain Capital. He ran for a Senate seat in Massachussetts in 1994, but lost to Ted Kennedy (both pics AP)

Family is important to both men. The Romneys have five sons, who are all grown up now, and 18 grandchildren, which makes family events very busy

Obama has a busy schedule as president, but he tries to eat dinner with Michelle and their two daughters, Sasha and Malia, most nights a week. They're the first couple since Jimmy Carter's presidency, more than 30 years ago, to live in the White House with young children

Obama in 2004, as a new senator preparing for his speech at the Democratic National Convention, which shot him to prominence on the national stage. Romney's turnaround of the 2002 Winter Olympics gave him the momentum to enter the race for - and win - the governorship of Massachusetts (AP/Getty)

Both men like to keep fit. Obama loves to play basketball, and is said to be very competitive. Romney here receives a Boston Celtics jersey, although he prefers participating in other sports (AFP/AP)

What is it about presidents and golf? Obama plays a lot - though he admits he is not much good at it and says he just enjoys being out in the open air. Romney clearly likes the open air - or open water. Here he is taking a dip in the lake by his holiday home in New Hampshire (both pics AP)