(Corrects paragraph 3 to show Marin resigned last month)
By Steve Holland and Heather Timmons
WASHINGTON (Reuters) -Senate Republican leader Mitch McConnell's unexplained freezeup while speaking in Congress this week is the latest reminder that America's most powerful political leaders are much older than many in other democracies.
Joe Biden, 80, is the oldest U.S. president to ever serve in the White House, and nearly two decades older than the median age of the world's national leaders, 62, Pew Research found.
While Biden is younger than 89-year-old President Paul Biya of Cameroon, the world's oldest head of state, he could be a grandfather to Chilean President Gabriel Boric or Sanna Marin, who stepped down as Finland's prime minister last month. Both are 37.
Yet Biden is years younger than some members of the U.S. Congress.
McConnell, 81, stopped talking mid-sentence at a news conference on Capitol Hill on Wednesday and stood mutely for 23 seconds until he was led away from reporters, only to return later to report, "I'm fine."
The moment sparked worries about his mental fitness, especially after he was hospitalized and treated for a concussion after a fall in March. Republican Senator Chuck Grassley of Iowa, 89, Democratic Senator Dianne Feinstein of California, 89, and Vermont Senator Bernie Sanders, 81, are older than McConnell.
Many congressional lawmakers are in their 70s, and the median age of the Senate is 65.3, FiveThirtyEight calculated, the oldest ever, versus a median age of 38.8 years in the United States as a whole.
At 64, the U.S. Senate has the seventh-highest average age of any parlimentary body, the Interparlimentary Union calculates, topping countries with much older populations including Japan, Italy and Greece.
Biden's advanced age has raised questions about whether he should stand for a second term. The president recently tripped over a sandbag on stage, walks with a careful gait and is prone to verbal slip-ups.
He may face Donald Trump, 77, as the Republican nominee in the 2024 election. Reuters polling shows many Americans think neither should run because of their age.
Asked about Biden's age, the White House points to accomplishments, including the 2020 presidential election, helping Democrats stave off loses in the 2022 elections and getting a host of legislation through Congress as president.
Biden doesn't make the top 10 of the world's oldest currently serving leaders, according to Pew, which in addition to Biya is led by Mahmoud Abbas, president of the Palestinian Authority, at age 87.
(Reporting By Steve Holland and Heather Timmons; Editing by Cynthia Osterman and)
