A dozen demonstrators, including past NOW president Eleanor Smeal, were arrested yesterday outside the Vatican embassy here in a carefully choreographed climax of a rally protesting the Roman Catholic Church's stand on abortion, homosexuality, birth control and women's rights.

Yesterday's protest, sponsored by the ad hoc Papal Visit Coalition of both Catholic and non-Catholic groups, was the first in a series of demonstrations planned by the group between now and Sept. 10, when Pope John Paul II arrives in Miami to begin a 10-day tour of the United States.

Fewer than 100 demonstrators gathered in an empty lot at 36th Street and Massachusetts Avenue NW, two blocks north of the Vatican embassy, the Apostolic Nunciature, to hear speakers condemn Catholic teachings on sexual morality.

"Because of my sex, I am second-class forever in my church," said Smeal. "Because of my sex I could have been condemned {by the church} to death at an early age," had she not defied the church ban on birth control.

Her family background, she explained, includes a history of "Mediterranean anemia -- a disease which does not do well in pregnancy . . . . "

Frances Kissling, head of Catholics for a Free Choice, who also was arrested, said there are a half million maternal deaths annually in developing countries around the world "as a result of {Vatican} policies" opposing birth control and abortion.

"Because of the sinful sexist stance of the Catholic Church, women are denied ordination," said Ruth Fitzpatrick of the Women's Ordination Conference. "We will not accept men telling women they can't be priests because that's the way God wants it; She does not!"

The Catholic Church has "mutilated the body of Christ" through its treatment of blacks as well as homosexuals, said Renee McCoy of the National Coalition of Black Lesbians and Gays.

"When you want to find God, do not look into the face of the pope; look into the faces of your gay and lesbian brothers and sisters who hide in terror from the church . . . dying of AIDS."

The demonstrators, arrested for protesting within 500 feet of an embassy, were released late yesterday and ordered to reappear for disposition of their sentences today in U.S. District Court. The charge carries a maximum 60-day jail term and a $100 fine upon conviction.

Carefully separated by police from the protest, about a dozen counterdemonstrators marched along Massachusetts Avenue 500 feet in the opposite direction, carrying signs proclaiming, "God Bless John Paul II."