MADRID -- Hundreds of thousands of demonstrators took to the streets here yesterday in support of marriage as a union between a man and a woman, and against a pending vote in Parliament to redefine it as an institution open to all regardless of sexual orientation.
The proposed change to the Spanish civil code is considered likely to pass a final hurdle in the Senate on June 30 and clear the way for gay marriage and the adoption of children by gay spouses in Spain by the end of the summer. Leaders on both sides of the deeply divisive issue recognize that the proposed law is part of a rapid and dramatic push toward secularization in what was once one of the most devoutly Catholic countries in Europe.
At yesterday's rally, which clogged the streets of the nation's capital, an array of activist groups, including the conservative Popular Party and various Catholic and ''pro-family" organizations from 60 countries, sought to thwart what they see as radical social engineering and gathered under a banner proclaiming, ''Madrid, World's Capital of Family."
Leaders of the demonstration said that they do not oppose civil unions for gay couples and that they support equal rights for gays and gay couples, particularly regarding pensions, inheritance, and tax breaks.
But the organizers said they came together to oppose adoption rights for gay couples and the move to legally redefine matrimony, which they believe refers to a traditional, religious sacrament between a man and a woman and which they feel provides the ''cornerstone of the family."
Benigno Blanco, vice president of the Spanish Family Forum, one of the lead organizers of the march, said the demonstration ''is for the defense of family and specifically for the right of children to have a father and a mother.
''It is to give a big 'yes' to family, but we are not going against anybody," he added.
Madrid's central thoroughfare was a sea of demonstrators -- secular, religious, young, old -- waving Spanish flags and placards that read, ''Matrimony: Man and Woman."
At the front of the march were thousands of young families, with parents carrying children on their shoulders and pushing strollers. Children held balloons that read, ''Yes, the family is sacred."
The crowd was estimated by police at 200,000 and by organizers as much higher. It wound through the central city and gathered in the Puerta del Sol, the historic gateway to the city, under the watchful eye of bronze statues of Spain's Catholic kings, where speeches were delivered by several Catholic bishops, political leaders, and activists.
Sharon Slater, president of the Arizona-based, ecumenical organization United Families International, told the crowd: ''This is a powerful moment that marks the beginning of a world movement. Starting today, the families of the world are not going to be quiet in the end that hurts men, women, and especially children."
The Rev. Juan Jose Perez-Soba, 40, a professor of theology in a Catholic seminary in Madrid, said in an interview that marriage is ''a sacrament grounded in religious tradition between a man and a woman toward the natural instinct to create life. When the government tells us the word 'matrimony' means something different, they degrade its true meaning for heterosexuals. And that is unjust."
But supporters of gay marriage in Spain say notions of marriage and family -- like other ideas ranging from who has the right to vote, to the legal definition of what constitutes life -- have evolved and changed within modern democracies.
They say the institution of marriage must also be transformed to be inclusive for everyone regardless of sexual orientation.
Juan Fernando Lopez Aguilar, justice minister in the Socialist Party's government, penned what he called ''a concise and simple change" to Article 44 of the civil code establishing that every person has the right ''to accept the rights and duties of matrimony as a form of civil contract regardless of the sex of the partners."
''Marriage is a sacrament for many people in this country, and they have our full respect," he said in an interview. ''But we must also consider that marriage is a civil contract and that it therefore must be extended to all citizens fairly and equally."
Several hundred supporters of the proposed law organized a small counterdemonstration in Madrid earlier in the day, seeking shade from the hot midday sun underneath a large, abstract marble monument titled ''The Constitution of 1978." The Spanish Constitution was established three years after the death of dictator Francisco Franco in 1975.
''We believe democracy is not stagnant; it involves evolution and maturity," said Sylvia Jaen, spokeswoman for the State Federation of Lesbians, Gays, and Transsexuals. ''What is happening in Spain now is part of the evolution of our democracy."
Her group and others are planning a massive gay pride march July 2 to celebrate what they anticipate will be the passage of the law June 30.
If the measure passes, Spain would become the second European country to legalize gay marriage and the adoption of children by gay couples. The Netherlands enacted its gay marriage law in 2001. Belgium also legalized gay marriage but has not yet ruled on adoption.
Passage of the law would mark a stunning transformation for the Catholic country in its 30-year process of creating a modern democracy following Franco's death.
Just a generation ago under Franco, whose dictatorial rule was blessed by the Catholic Church, homosexual acts were illegal and thousands of homosexuals were shipped off to institutions that gay activists say were tantamount to concentration camps.
Now, the idea of giving gays equal rights to marriage is supported by a solid majority.
A recent public opinion poll by the Madrid-based Center for Sociological Research, a leading and independent pollster, suggested that 66 percent of Spaniards believe ''homosexuals should have a right to get married."
The debate in Spain is playing out amid the ruling Socialist Party's head-on confrontation over a host of social issues with the politically powerful hierarchy of the church and the conservative parties that have historically been aligned with the church.
After being swept into power by a tumultuous election in the immediate aftermath of the March 11, 2004, train bombings in Madrid, the Socialist Party has put forth an agenda that includes ending mandatory religion classes in public schools, reconsidering euthanasia and divorce laws, and easing restrictions on abortion.
Prime Minister Jose Luis Rodriguez Zapatero's government has even opened up discussion on the previously sacrosanct policy in which the Spanish government provides the church, and some 40,000 institutions affiliated with it, one-third of their total budget.
But as divisive as the debate has been, the lines of confrontation are often blurred. Some Catholic organizations support gay marriage, and some Socialist Party voters oppose it.
Two close friends, who embody the complexity of the issue, met in a Madrid park yesterday morning.
Juan Jose Broch, 41, and Lourdes Azorin, 47, came together as volunteers in a Catholic charity. Both see themselves as devout Catholics. Broch is gay, and Azorin is a widow who was married for 10 years before her husband died of lung cancer five years ago.
Broch, who works in a local child protective services office, says he believes gay marriage is an essential part of achieving full equality for the gay community.
Azorin, a psychotherapist, says she believes wholeheartedly in the fight for equal rights for gays, including civil unions and adoption of children.
But she said she believes marriage is a religious sacrament between a man and a woman. She believes homosexual unions can be the loving basis to raise a family, but should not be called marriage or matrimony and that to do so would diminish the institution of marriage.
They left each other in the park as Broch headed off to the demonstration in favor of gay marriage and Azorin headed off to the demonstration in support of heterosexual-only marriage.
''We will always be friends, and we will just keep talking about it," Azorin said. ''We are going to have dinner tonight. We never give up trying to understand each other."
Charles M. Sennott can be reached at email@example.com.