"We cannot welcome this pope until he begins to do away with the church's continuing violence of sexism," said Sister Donna Quinn, coordinator of the National Coalition of American Nuns.
Participants in the service will include Rose Marie Hudson and Elsie McGrath, who were excommunicated last month by Archbishop Raymond Burke of St. Louis because they were ordained as part of a women-priest movement condemned by the Vatican.
"In the face of one closed door after another, Catholic women have been innovative, courageous and faithful to the church," said Aisha Taylor, executive director of the Women's Ordination Conference. "They continue to make a way where is none."
Gay Catholic activists, who plan to demonstrate Tuesday along the papal motorcade route in Washington, have compiled a list of statements by Benedict during his career which they consider hostile to gays and lesbians. These include forceful denunciations of gay marriage and of adoption rights for same-sex couples.
"He has issued some of the most hurtful and extreme rhetoric against our community of any religious leader in history, and we want to call him into account for the damage that he's done," said Marianne Duddy-Burke, executive director of DignityUSA.
Duddy-Burke said she hopes the protests will be coupled with celebration of the gains made by gay Catholics in America in recent years. She cited the growing number of parishes welcoming openly gay members and the dozens of Catholic colleges that now have gay-straight alliances.
Another gay Catholic group, New Ways Ministry, hosted a news conference at which speakers conveyed what they would tell the pope if they had the opportunity. The speakers included Gregory Maguire, author of the best-selling novel "Wicked," who along with husband Andrew Newman is raising three adopted children as Catholics in Massachusetts, the only state to allow same-sex marriages.
"We invite you to spend a day, a meal, a weekend with us," Maguire said in his message to the pope. "We don't want to serve as a poster-family for gay Catholics. ... We will just be ourselves, in all our confusion, aspiration, need and joy."
Another divisive issue being raised this week is the Vatican's ban on contraception. Gay rights groups and others say the ban undermines programs promoting condom use to curb the spread of HIV/AIDS.
In a conference call Monday organized by Catholics for Choice, four Catholic theologians will be examining the impact of the 1968 encyclical "Humanae Vitae," which defined the Vatican's opposition to artificial birth control.
"Catholics wonder why there's this huge disparity between what the hierarchy says we should do in regard to contraception and what Catholics on the ground actually do," said Catholics for Choice president Jon O'Brien.
He termed the ban "a great tragedy ... a policy that lacks compassion and understanding."
Asked about the prospects that Benedict might reconsider the ban, O'Brien replied, "I do believe in miracles."
For many American Catholics, the most distressing church-related issue of recent years has been clerical sex abuse. Thousands of molestation allegations have been filed against Catholic clergy, and dioceses have paid out more than $2 billion in claims since 1950.
David Clohessy, national director of the Survivors Network of those Abuse by Priests, said his advocacy group would not be mollified even if the pope meets privately with abuse victims.
"Extraordinarily few Catholics and victims will be moved in any way by gestures, words, tokens," Clohessy said. "It's as plain as day that three years into his papacy, Benedict has done literally nothing to protect the vulnerable or heal the wounded."
Clohessy said his group will make use of the papal visit to press for tough disciplinary action against bishops who covered up abuses by their priests and to urge pre-emptive steps by the Vatican against abuse by priests in other nations.
Clohessy expressed disappointment that the pope was not visiting Boston, where the scandal burst into the national spotlight in 2002.
"Showing a willingness to visit the epicenter of the crisis - that would have been one gesture that might have been effective," Clohessy said.
Voice of the Faithful, a Boston-based reform group which emerged from the scandal, placed a full-page ad last week in The New York Times, costing more than $50,000, to air its call for a transformation of the church.
The ad urged Benedict to meet with abuse victims, oust bishops who covered up abuse and promote a greater role for lay Catholics in running their parishes.
The extent to which the pope addresses the varied grievances during his trip remains unknown. But the Vatican's envoy to the United States, Archbishop Pietro Sambi, said any dissent that might arise was regrettable.
"Even in the Catholic church, nobody has the right to instrumentalize the visit of the pope to serve their personal interests," Sambi told the National Catholic Reporter. "The problem is that there are too many people here who would like to be the pope ... and who attribute to themselves a strong sense of their own infallibility."
