Four Catholic bishops have said “special” marriage laws should remain unchanged to protect the “unique sacrifices” of straight couples who have children.

In response to proposed equal marriage rights in Washington state, the Archbishop of Seattle is among four Catholic leaders to argue marriage “is grounded not in faith, but in reason and the experience of society” and should not be expanded to include gay couples .

They claim the prohibition on marriage between close relation is “a clear indication that the definition of marriage is related to bringing children into the world and the continuation of the human race” and equal marriage rights are “not in the public interest.” There is no expressly religious element to the argument.

The bishops reacted to an announcement that equal marriage legislation would be laid in the state legislature’s first session of the year.

Governor Christine Gregoire told a news conference in Olympia earlier this month: “It is time in Washington state for marriage equality. It’s the right thing to do.”

The bishops wrote in response that: “Marriage in faith and societal traditions is acknowledged as the foundation of civilization. It has long been recognized that the stability of society depends on the stability of family life in which a man and a woman conceive and nurture new life.

“In this way, civil recognition of marriage has sought to bestow on countless generations of children the incomparable benefit of a loving mother and father committed to one another in a lifelong union.”

Continuing the secular argument, they said: “Were the definition of marriage to change, there would be no special laws to support and recognize the irreplaceable contribution that these married couples make to society and to the common good by bringing to life the next generation.”

“A change in legislation would mean that the state would no longer recognize the unique sacrifices and contributions made by these couples, thereby adding to the forces already undermining family life today.”

Archbishop J. Peter Sartain of Seattle, Bishop Blase J. Cupich of Spokane, Bishop Joseph J. Tyson Bishop of Yakima and Auxiliary Bishop of Seattle Eusebio Elizondo, M.Sp.S put their names to the statement.