Associated Press

Sen. Orrin Hatch and his Democratic challenger Scott Howell battled over age in the Senate after Howell sent out a fundraising email saying, "Look, Orrin Hatch is not a bad guy. But he's an old guy. . . . We cannot risk the possibility of an 80-year-old man taking office, only to retire or die before his term is through."

At 78, Hatch has served in the Senate for 36 years. He is the seventh oldest in the U.S. Senate, where the median age is 63. Here's a look at the 27 U.S. Senators who are 70 or older.

Read more: Scott Howell, Sen. Orrin Hatch in war of words over age

Frank Lautenberg, D-N.J.
Associated Press

Date of birth: January 23, 1924
Took office: January 3, 2003
Age at taking office: 78 years
Current age: 88 years

According to his biography, Lautenberg's parents were Polish and Russian immigrants who came to the United States through Ellis Island. Lautenberg served in the Army Signal Corps in Europe, attended Columbia University on the G.I. Bill, and graduated with a degree in economics. He was first elected to the Senate in 1982. He briefly retired after his third term and returned to the Senate in 2002.

Daniel Inouye, D-Hawaii
Associated Press

Date of birth: September 7, 1924
Took office: January 3, 1963
Age at taking office: 38 years
Current age: 88 years

According to his biography, Inouye served in World War II as a member of the Japanese American 442nd Regimental Combat Team. He was awarded the Medal of Honor in 2000. Inouye earned a J.D. degree at George Washington Law School and was elected to the Senate in 1962. He is the first Japanese American to serve in the U.S. House of Representatives and later the first in the Senate.

Daniel Akaka, D-Hawaii
Associated Press

Date of birth: September 11, 1924
Took office: May 16, 1990
Age at taking office: 65 years
Current age: 88 years

According to his biography, Akaka served as a civilian worker in the U.S. Army Corps of Engineers from 1943 to 1945 and then in active duty in the U.S. Army from 1945 to 1947. Akaka was first elected to the U.S. House in 1976 and was appointed to the Senate when Sen. Spark Matsunaga passed away. Akaka is reportedly retiring after this term.

Richard Lugar, R-Ind.
Associated Press

Date of birth: April 4, 1932
Took office: January 3, 1977
Age at taking office: 44 years
Current age: 80 years

According to his biography, Lugar is the longest serving member of Congress in Indiana history. Lugar attended Pembroke College at Oxford University as a Rhodes Scholar and volunteered for the U.S. Navy in 1957. Lugar was elected to the Senate in 1976.

Dianne Feinstein, D-Calif.
Associated Press

Date of birth: June 22, 1933
Took office: November 10, 1992
Age at taking office: 59 years
Current age: 79 years

Feinstein earned a bachelor's degree in history from Stanford University in 1955 and served as the mayor of San Francisco from 1978 through 1988. According to her biography, Feinstein serves as the Chairwoman of the Senate Select Committee on Intelligence, and is also a member of the Senate Judiciary Committee and the Senate Appropriations Committee.

Chuck Grassley, R-Iowa
Associated Press

Date of birth: September 17, 1933
Took office: January 3, 1981
Age at taking office: 47 years
Current age: 79 years

According to his biography, Grassley earned a bachelor's degree in 1955 and a master's degree in political science in 1956. He did his Ph.D. work at the University of Iowa. Grassley worked as a farmer, assembly line worker and sheet metal shearer before being elected to the Iowa Legislature in 1958, the U.S. House of Representatives in 1974 and the Senate in 1980.

Orrin Hatch, R-Utah
Associated Press

Date of birth: March 22, 1934
Took office: January 3, 1977
Age at taking office: 42 years
Current age: 78 years

According to his biography, Hatch was a card-carrying member of the AFL-CIO and worked his way through Brigham Young University, graduating in 1959 with a degree in history. He received his Juris Doctorate from the University of Pittsburgh Law School. He worked as an attorney until his election to the Senate in 1976.

Richard Shelby, R-Ala.
Associated Press

Date of birth: May 6, 1934
Took office: Janaury 3, 1987
Age at taking office: 52 years
Current age: 78 years

According to his biography, Shelby is a graduate of the University of Alabama's undergraduate and law programs. He served four terms in the U.S. House of Representatives and eight years in Alabama's legislature before his election to the Senate.

Carl Levin, D-Mich.
Associated Press

Date of birth: June 28, 1934
Took office: January 3, 1979
Age at taking office: 44 years
Current age: 78 years

According to his biography, Levin comes from Detroit. He was educated at Swarthmore college and Harvard Law School. He was elected to the Detroit City Council in 1969 and the U.S. Senate in 1978. He currently serves as chairman of the Senate Armed Services Committee.

Jim Inhofe, R-Okla.
Associated Press

Date of birth: November 17, 1934
Took office: November 17, 1994
Age at taking office: 60 years
Current age: 77 years

According to his biography, Inhofe graduated from the University of Tulsa with a degree in economics. He served in the U.S. Army and worked as a small businessman in aviation, real estate and insurance. He also served in the Oklahoma House of Representatives, the Oklahoma Senate, the U.S. House of Representatives and as the mayor of Tulsa.

Herb Kohl, D-Wis.
Associated Press

Date of birth: Feburary 7, 1935
Took office: January 3, 1989
Age at taking office: 53 years
Current age: 77 years

According to his biography, Kohl earned his bachelor's degree from the University of Wisconsin-Madison in 1956 and his master's degree from Harvard University in 1958. He also served in the Army Reserve from 1958 to 1964. Kohl helped build his family business, Kohl's grocery and department stores, and served as president of the corporation from 1970 through 1979. He bought the Milwaukee Bucks in 1985 in order to keep the team in Milwaukee. He does not plan to run for reelection.

Pat Roberts, R-Kansas
Associated Press

Date of birth: April 20, 1936
Took office: Jan. 3, 1997
Age at taking office: 60 years
Current age: 76 years

According to his biography, Roberts was born in Topeka, Kansas, and earned his journalism degree from Kansas State. He served in the U.S. House of Representatives for 16 years before being elected to the Senate. He is the ranking member of the Senate Agriculture Committee.

Barbara Mikulski, D-Md.
Associated Press

Date of birth: July 20, 1936
Took office: January 3, 1987
Age at taking office: 50 years
Current age: 76 years

According to her biography, Mikulski worked as a social worker in Baltimore, which then evolved into community activism. She was elected to the Baltimore city council in 1971, where she served for five years. She was elected to the House of Representatives in 1976 and the Senate in 1986.

John McCain, R-Ariz.
Associated Press

Date of birth: August 29, 1936
Took office: January 3, 1987
Age at taking office: 50 years
Current age: 76 years

According to his biography, McCain attended college at the United States Naval Academy, which launched a 22-years career as a naval aviator. He was taken prisoner during the Vietnam War and was held in "Hanoi Hilton." He retired from the Navy in 1981 and was elected to the U.S. House of Representatives in 1982.

Jay Rockefeller, D-W.Va.
Face the Nation

Date of birth: June 18, 1937
Took office: January 15, 1985
Age at taking office: 47 years
Current age: 75 years

According to his biography, Rockefeller graduated from Harvard University in 1961 with a bachelor's degree in Far Eastern Languages and History. He first came to West Virginia in 1964 as a 27-year-old VISTA volunteer. He was elected to the West Virginia House of Delegates in 1966 and to the office of West Virginia Secretary of State in 1968. He was elected governor of West Virginia in 1976 and went to the Senate in 1984.

Thad Cochran, R-Miss.
Associated Press

Date of birth: December 7, 1937
Took office: December 27, 1978
Age at taking office: 41 years
Current age: 74 years

According to his biography, Cochran enrolled in the school of liberal arts at the University of Mississippi in 1955. He earned a bachelor's degree in psychology and a minor in political science. In 1959, Cochran was commissioned as Ensign in the U.S. Naval Reserve and served on the USS MACON before graduating from the U.S. Navy School of Justice. He enrolled in the School of Law at the University of Mississippi and served as a member of Congress before being elected to the Senate.

Tom Harkin, D-Iowa
Associated Press

Date of birth: November 19, 1939
Took office: January 3, 1985
Age at taking office: 45 years
Current age: 72 years

According to his biography, Harkin was born in Cumming, Iowa, (pop. 150) and still lives in the house where he was born. He attended Iowa State University on a Navy ROTC scholarship and earned a degree in government and economics. He served in the Navy as a jet pilot on active duty from 1962 to 1967. He first went to Washington in 1969 as a staff member and was elected to Congress in 1974.

Harry Reid, D-Nevada
Associated Press

Date of birth: December 2, 1939
Took office: January 3, 1987
Age at taking office: 47 years
Current age: 72 years

According to his biography, Reid graduated from Utah State University in 1961 and went on to earn a law degree from George Washington University. As a law student, he worked nights as a U.S. Capitol police officer. He was elected to the Nevada State Assembly in 1968 and won the first of his two terms in the U.S. House of Representatives in 1982. He is currently the Senate Majority Leader.

Patrick Leahy, D-Vt.
Associated Press

Date of birth: March 31, 1940
Took office: Janaury 3, 1975
Age at taking office: 34 years
Current age: 72 years

According to his biography, Leahy received his Juris Doctorate from Georgetown University Law Center and served for eight years as state's attorney in Chittenden County, Maryland. He is currently the chairman of the Senate Judiciary Committee. When he was elected to the Senate, he was the youngest U.S. senator to ever be elected from Maryland.

Lamar Alexander, R-Tenn.
Associated Press

Date of birth: July 3, 1940
Took office: January 3, 2003
Age at taking office: 62 years
Current age: 72 years

According to his biography, Alexander is a seventh generation Tennessean. He has been the U.S. Education Secretary, University of Tennessee president and professor at Harvard's School of Government. Additionally, he chaired the National Governors' Association and President Ronald Reagan's Commission on Americans Outdoors.

Barbara Boxer, D-Calif.
Associated Press

Date of birth: November 11, 1940
Took office: January 3, 1993
Age at taking office: 52 years
Current age: 71 years

Boxer graduated from Brooklyn College with a bachelor's degree in 1962. She worked as a congressional aide from 1974 through 1976, and was elected to the U.S. House of Representatives in 1983. She was elected to the Senate in 1992. According to her biography, Boxer is the first woman to chair the U.S. Senate's Committee on Environment and Public Works.

Ben Nelson, D-Neb.
Associated Press

Date of birth: May 17, 1941
Took office: January 3, 2001
Age at taking office: 59 years
Current age: 71 years

According to his biography, Nelson earned a bachelor's degree in 1963, a master's degree in 1965 and a law degree from the University of Nebraska in 1970. He was elected as the governor of Nebraska in 1990, re-elected to the position in 1994, and ran for the Senate in 2000. He does not plan to run for reelection.

Bernie Sanders, I-Vt.
Associated Press

Date of birth: September 8, 1941
Took office: January 3, 2007
Age at taking office: 65 years
Current age: 71 years

According to his biography, Sanders was elected to the Senate after serving 16 years in the House of Representatives. He is the longest-serving independent member of Congress in American history. Sanders graduated from the University of Chicago in 1964 before moving to Vermont.

Max Baucus, D-Mont.
Associated Press

Date of birth: December 11, 1941
Took office: December 15, 1978
Age at taking office: 37 years
Current age: 70 years

According to his biography, Baucus earned a Bachelor of Arts degree in 1964 and a law degree from Stanford University in 1967. He served in the Montana State House of Representatives from 1973 through 1974 and the U.S. House of Representatives from 1974 through 1978. He was then elected to the Senate.

Mitch McConnell, R-Ken.
Associated Press

Date of birth: Febuary 20, 1942
Took office: January 3, 1985
Age at taking office: 42 years
Current age: 70 years

According to his biography, McConnell graduated from the University of Louisville College of Arts and Sciences and the University of Kentucky College of Law. He worked as a Capitol Hill intern and chief legislative assistant, as well as a deputy assistant attorney general to President Gerald Ford. McConnell is the Senate Republican Leader.

Joe Lieberman, I-Conn.
Associated Press

Date of birth: Feburary 24, 1942
Took office: January 3, 1989
Age at taking office: 46 years
Current age: 70 years

According to his biography, Lieberman received his bachelor's degree from Yale College in 1964 and his law degree from Yale Law School in 1967. He served in the Connecticut State Senate in 1970 before returning to private legal practice and serving as Connecticut's 21st Attorney General. Lieberman plans to retire at the end of his term.

Jon Kyl, R-Ariz.
Associated Press

Date of birth: April 25, 1942
Took office: Janaury 3, 1995
Age at taking office: 52 years
Current age: 70 years

According to his biography, Kyl received his bachelor's and law degrees from the University of Arizona. He practiced law at Jennings, Strouss & Salmon in Phoenix and was chairman of the Phoenix Chamber of Commerce. He is currently the Republican Whip in the Senate, and does not plan to run for reelection.