List of 2012 Republican Presidential Candidates by Age

• 76 Ron Paul (August 20, 1935) - Six days after President Roosevelt signed the Social Security Act into law
• 68 Newt Gingrich (June 17, 1943) & Buddy Roemer (October 4, 1943) - Newt was born on the same day as Barrry Manilow
• 64 Mitt Romney (March 12, 1947) - The day of the Truman Doctrine aka the start of the Cold War 
• 61 Rick Perry (March 4, 1950) - Same day as Emilio Estefan
• 53 Rick Santorum (May 10, 1958) - The number one song was Witch Doctor by David Seville
• 51 Jon Huntsman (March 26, 1960) -  Iraq executed 30 for attack on Pres Kassem

Sources:

http://www.ssa.gov/history/tally.html

http://www.history.com/this-day-in-history/truman-doctrine-is-announced

http://www.menziesera.com/number_1_hits/1958.shtml

http://www.historyorb.com/date/1960/march/26