The gift of faith is like walking on the moon; it requires a giant step. But faith can be tougher than space travel, which is based on the laws of science. Faith demands that its followers embrace doctrines administered by men. For the nearly 1 billion Roman Catholics around the world, that binding authority rests with one person, the Pope. Last weekend, when John Paul II visited Germany, the growing gap between his conservative preaching and the local groundswell for reform was plain for all to see. < /P>

About 28 million Germans profess Roman Catholicism. But on the eve of the Pope's two-stop visit, the newspaper Die Woche reported that 34% of German Catholics under the age of 29 have considered leaving their church solely because of the doctrinal stan ce of the man heading it. This opinion of John Paul II's papacy is shared by 28% of those polled in the 30-to-49 age group and even 16% of those over 49.

Opposition, though, could not stop the parade in Paderborn, the northern German city where John Paul arrived on Friday evening and where 150,000 of the faithful came--many of them bused in from Poland and the Czech Republic--for an open-air Mass on Sat urday morning. Nearly as many were expected on Sunday in Berlin at the Olympic Stadium, though only 400,000 of the 3.5 million Berliners are Catholic. The emotional high point of the visit was expected to be the sight of John Paul II and Chancellor Helmut Kohl walking together through the Brandenburg Gate to mark the momentous change that has taken place since the Pope's last visit in 1987: German unification.

John Paul II has mastered the style of the foreign visit in the 72 he has made in his 18 years as Pope, and he has encountered numerous critics. But he has rarely run into the opposition he confronted in Germany, where his stands on birth control, celi bacy for priests, ordination of women, homosexuality, divorce and other doctrinal issues are hotly contested. In Berlin an "Anti-Pope Council" of homosexual men and women, feminists and atheists planned a march to coincide with his visit. Demons trators also declared a "Pope-free zone" at the old East-West crossover, Checkpoint Charlie, on Friedrichstrasse. Concerned, the Vatican called the archbishops of Paderborn and Berlin to Rome in early June to be reassured that protesters would b e kept at a distance.

Harder to fend off than flamboyant marchers is the increasing rebellion of Catholics in the pews and theologians in the press. Says one of the most strident and longtime critics, Hans Kung, a professor of ecumenical theology who was removed from his ch air in Catholic religion at the University of Tubingen for his sustained attacks on Vatican policy: "The problem with this Pope isn't his humanity, it's his theology." The problem for Kung and other critics is that John Paul's conservative theol ogy is underpinned by the dogma set down at the First Vatican Council in 1870: on matters of faith and morals, the Pope is infallible. But while the Pope has the power, the reformers have growing popular support. In a Die Woche survey last August, 84% of German Catholics opposed mandatory celibacy for priests, 75% favored ordination of women and 85% doubted papal infallibility. "Do you consider the Catholic Church antisex?" the people were asked, and two-thirds responded, "Ja." Some 1. 5 million German Catholics last year signed a petition asking for church reforms. Echoing the "We Are One People" movement of German unification, this one calls itself "We Are the Church." Moreover, 500,000 Austrian Catholics have sign ed similar petitions, as have more than 70,000 Catholics in Switzerland.

The discontent is reflected in falling church membership in Germany. More than 150,000 Germans--roughly the same number of people who greeted the Pope in Paderborn--quit the Catholic Church each year, and some Catholics are becoming increasingly hostil e in their criticism. Uta Ranke-Heinemann, the daughter of a former German President and the first woman to hold a university chair in Catholic theology, wrote in the Berliner Zeitung before the Pope visited that he is "an affliction for women" and deplored the "nonsense" he writes about them. Says the prominent Tubingen theology professor Norbert Greinacher, a Catholic: "Of course, the right wing of the Catholic Church will give the Pope a good reception, but that is not the hear t of my church."

Even the most powerful Catholic in Germany, Chancellor Kohl, joined part of the chorus of dissent. In a previsit interview, while full of praise for John Paul generally, Kohl said regarding the Pope's stance on birth control, "For me, that is a qu estion of personal conscience." Theologian Kung, during a Berlin protest two weeks ago, said the Catholic Church is "a ship that has lost its course" and the person to blame is "the captain." But the man at the helm of the ship of St. Peter still believes that his views strengthen rather than weaken the church, and so he holds his course despite the gathering storm.

--Reported by Richard Ostling/New York and Bruce van Voorst/Bonn