OLYMPIA, Wash. (EWTN News/CNA)—Proposed same-sex “marriage” legislation in Washington state would add to “the forces already undermining family life today,” the state’s Catholic bishops warned.

In a January 2012 statement, the bishops stressed that the “stability of society depends on the stability of family life, in which a man and a woman conceive and nurture new life.”

They noted in their letter, titled “Marriage and the Common Good,” that the civil recognition of marriage as between one man and one woman has given “countless generations of children the incomparable benefit of a loving mother and father committed to one another in a lifelong union.”

On Jan. 13, 23 senators, including two Republicans, introduced legislation that would grant marriage licenses to same-sex couples. Gov. Christine Gregoire, a Catholic Democrat, had requested the bill, which will require 25 votes to pass the state Senate.

In response to the move, the bishops explained that when defining marriage in terms of the relationship between a man and a woman and its “important role” in guaranteeing future generations the state recognizes the “irreplaceable contribution” married couples make to society.

Changing the definition of marriage means there are no special laws to support and recognize this contribution, they said.

Marriage not only creates a bond through a personal relationship, but allows the potential “of a man and woman to conceive and nurture new life, thus contributing to the continuation of the human race.”

The bill’s chief sponsor, state Sen. Ed Murray, D-Seattle, however, criticized the bishops in remarks to The Associated Press.

“My first reaction, as a practicing Catholic, is that this is very hurtful,” said Murray, who is currently in a 20-year same-sex relationship.

Joseph Backholm, executive director of the Family Policy Institute of Washington, said that he expects thousands of people to show up at the bill’s first public hearing on Jan. 23 to show their opposition.

But he sided with the bishops, saying that the “idea that there is no difference between a heterosexual relationship and a homosexual relationship and that the law should recognize no difference assumes there is no difference between men and women.”

“This would be the state taking a position and saying, ‘We will no longer encourage arrangements that will give children both a mother and father,’” he added.

Washington state passed a domestic-partnership law in 2007, and there are about 19,000 registered domestic partners in the state today.

In their statement, the bishops called on local Catholics to contact state legislators and urge them to keep marriage defined as between one man and one woman.