It's getting to be routine: The National Press Club has elected a woman as president, its second since that venerable institution broke its historic policy of segregation by the sexes in 1971. On the third time, we promise not to take note of sex.

Mary Kay Quinlan, a correspondent for Gannett News Service, won the presidency uncontested. Also uncontested were the elections of Andrew Mollison of Cox Newspapers as vice president, Tom Squitieri of the Lowell (Mass.) Sun as secretary, and Peter Holmes of Nation's Business magazine as treasurer.

In contested elections, Arthur Jones of the National Catholic Reporter was chosen as financial secretary, and three persons were chosen as members of the board of governors: Kathryn S. Kahler of Newhouse News, Patrick McGrath of Metromedia News and Lee Roderick of the Scripps League of Newspapers. The officers serve one year, members of the board of governors for three years.

Quinlan's election came months after the National Press Club merged with the predominantly female Washington Press Club (previously known as the Women's National Press Club). The first woman president of NPC was Vivian Vahlberg, an Oklahoma newspaper correspondent, who was sworn in by President Reagan in 1982.