VATICAN CITY—No fewer than 10 Vatican department heads are celebrating their 75th year during the coming months. That's normal retirement age in the Roman Curia.

The birthdays give Pope John Paul II an opportunity to carry out a small revolution in his administrative ranks, yet no one expects wholesale personnel replacements in 1997.

The reason is that the 76-year-old Pontiff has increasingly allowed older officials to stay on the job. These members of the Vatican feel appreciated and are in no hurry to clean out their desks.

The Pope once told a group of senior citizens: “You should not stop nor consider yourselves in decline. You still have a mission to accomplish, a contribution to make.”

But the policy has unmistakably led to an aging of the Curia in recent years. Today, of the Vatican's 40 top managerial positions, more than a third are filled by prelates who will be 75 or older in 1997.

The average age of these department heads is more than 71 today, compared to 67 just a decade ago. There are relatively few younger faces, too: none are aged 60 or younger, compared to 10 in 1987.

Even some new appointees have tended to fall into the category of oldster. The head of the Congregation for Sacraments and Divine Worship, appointed a few months ago, just turned 70; the head of the Congregation for Sainthood Causes was 73 when named in 1995.

One factor in the natural aging of papal administrations is that new people nominated early in a pontificate tend to stick around, for one five-year term after another.

“If you bring in a man like Cardinal Ratzinger, where can he go later?” commented one longtime Vatican official. In fact, under Pope John Paul, no head of a curial congregation or council has ever gone back to a diocese.

Others note that Vatican careers are typically very long. Monsignors may spend several decades in the lower echelons, and most are nearing 70 by the time they reach the top of a department.

Some of the Curia bigs celebrating their 75th year in 1997 include Cardinal Pio Laghi, prefect of the Congregation for Catholic Education; Cardinal Bernardin Gantin, prefect of the Congregation for Bishops; Archbishop Alberto Bovone, prefect of the Congregation for Sainthood Causes; and Cardinal Roger Etchegaray, who heads the Pontifical Council for Justice and Peace and the Committee for the Great Jubilee of the Year 2000.

Needing fewer candles on his cake is U.S. Archbishop John Foley, president of the Pontifical Council for Social Communications, who will celebrate his 62nd birthday in 1997. When appointed to his position way back in 1984, he was the youngest person in charge of a major