WASHINGTON (CNS) -- Up to 25 U.S. bishops, including five cardinals, could retire because of age this year.

There are 14 still-active U.S. bishops, including three cardinals, who have already turned 75. Eleven more, including two cardinals, will celebrate their 75th birthday in 2007.

At age 75 bishops are requested to submit their resignation to the pope.

Cardinal Adam J. Maida of Detroit turned 75 March 18, 2005. He was bishop of Green Bay, Wis., before he was made archbishop of Detroit in 1990. He has been a cardinal since 1994.

Cardinal William H. Keeler of Baltimore turned 75 last March 4. Formerly bishop of Harrisburg, Pa., he has been archbishop of Baltimore since 1989 and a cardinal since 1994.

Cardinal Bernard F. Law, archpriest of St. Mary Major Basilica in Rome and a cardinal since 1985, turned 75 Nov. 4. A former bishop of Springfield-Cape Girardeau, Mo., he was archbishop of Boston from 1984 until his resignation in 2002 in the wake of the clergy sex abuse scandal there. He was named to his Rome post in 2004.

Cardinal Edward M. Egan of New York, whose 75th birthday is coming up April 2, will celebrate 50 years as a priest later this year. He was made a New York auxiliary bishop in 1985, bishop of Bridgeport, Conn., in 1988, archbishop of New York in 2000 and a cardinal in 2001.

Cardinal F. James Stafford, a Baltimore native who will mark his 75th birthday July 26, has been the Vatican's major penitentiary since 2003. Ordained a priest in 1957, he was made a Baltimore auxiliary in 1976 and bishop of Memphis, Tenn., in 1982. He became archbishop of Denver in 1986, president of the Pontifical Council for the Laity, 1996-2003, and a cardinal in 1998.

Pope John Paul II often asked cardinals to stay on the job after they reached the age of 75. So far Pope Benedict XVI has given no indication that he will change that practice. Even when a cardinal retires in his 70s, he remains an active member of the College of Cardinals, eligible to enter a conclave and vote for a new pope, until age 80.

The 11 other active U.S. bishops who are already 75 and the dates of their 75th birthday are:

-- Ruthenian Bishop Andrew Pataki of Passaic, N.J., Aug. 30, 2002.

-- Bishop Manuel Batakian of the Eparchy of Our Lady of Nareg in New York for Armenian Catholics, Nov. 5, 2004.

-- Bishop John J. Leibrecht of Springfield-Cape Girardeau, Mo., Aug. 8, 2005.

-- Bishop Carl F. Mengeling of Lansing, Mich., Oct. 22, 2005.

-- Bishop Raphael M. Fliss of Superior, Wis., Oct. 25, 2005.

-- Auxiliary Bishop Emil A. Wcela of Rockville Centre, N.Y., May 1, 2006.

-- Archbishop Thomas C. Kelly of Louisville, Ky., July 14, 2006.

-- Bishop Charles V. Grahmann of Dallas, July 15, 2006.

-- Archbishop Oscar H. Lipscomb of Mobile, Ala., Sept. 21, 2006.

-- Bishop Victor Balke of Crookston, Minn., Sept. 29, 2006.

-- Bishop John W. Yanta of Amarillo, Texas, Oct. 2, 2006.

The nine other currently active bishops, in addition to Cardinals Egan and Stafford, who will turn 75 in 2007 are:

-- Bishop John J. Nevins of Venice, Fla., Jan. 19.

-- Auxiliary Bishop A. James Quinn of Cleveland, April 8.

-- Auxiliary Bishop John M. Dougherty of Scranton, Pa., April 29.

-- Auxiliary Bishop Gilbert E. Chavez of San Diego, May 9.

-- Archbishop Elden F. Curtiss of Omaha, Neb., June 16.

-- Bishop James A. Murray of Kalamazoo, Mich., July 5.

-- Bishop James M. Moynihan of Syracuse, N.Y., July 6.

-- Bishop John M. D'Arcy of Fort Wayne-South Bend, Ind., Aug. 18.

-- Archbishop Alfred C. Hughes of New Orleans, Dec. 2.