During the 2008 election, Jennifer Roback Morse took a copy of a Canadian birth certificate wherever she went to speak in favor of California's Proposition 8.

A Catholic mother of two, Morse said she would furnish the document as proof that irreversible damage is done when a society changes the historical meaning of the word "marriage."

"On the certificate, there's a place for the mother's information, and where the father's information should be, there's a check box," she said in late January, as attorneys in San Francisco carried on a legal battle over the fate of same-sex marriage in California.

To Morse and thousands of others throughout the United States who prefer the traditional definition of marriage, that check box represents a sinister side-effect that she said has been overlooked in the Prop. 8 battle.

"Fatherhood is being diminished and marginalized," she said. "If we say that marriage is the union of any two persons, and there's no requirements to have a man and a woman, what we're really saying is that mothers and fathers are interchangeable."

Testimony in Perry vs. Schwarzenegger began on Jan. 11, and discussion in the courtroom has often lingered on the question of how gay marriage affects children--a central issue in the 2008 election. Final arguments in the federal trial, which is being heard by Judge Vaughn R. Walker, are expected later this year, possibly as soon as March.

Stephen F. Duncan, a professor of family and human development at Montana State University, wrote in 2000 that the percentage of American children living in single-mother households climbed from 6 percent in 1950 to 23 percent in 1998. But then, wrote Duncan, researchers began turning up evidence "that fathers were not 'optional family baggage,'" as Morse fears they would become under a redefined understanding of marriage.

In Growing Up With a Single Parent, a landmark 1994 text that examined the effects of divorce on children, Princeton University sociologist Sara McLanahan and Gary Sandefur of the University of Wisconsin-Madison claimed that research has demonstrated the importance of living with both biological parents.

"Children who grow up in a household with only one biological parent are worse off, on average, than children who grow up in a household with both of their biological parents, regardless of the parents' race or educational background, regardless of whether the parents are married when the child is born, and regardless of whether the resident parent remarries," they wrote.

Meanwhile, a 2006 study commissioned by the American Academy of Pediatrics claimed that children raised in a household with two lesbian mothers seemed to develop as normally as those living with a mother and a father.

While acknowledging that research of gay and lesbian parents is "just beginning," the authors asserted that "growing up with parents who are lesbian or gay may confer some advantages to children. They have been described as more tolerant of diversity and more nurturing toward younger children than children whose parents are heterosexual."

The Rev. Susan Russell of All Saints Episcopal Church in Pasadena said she has been "blessing" same-sex marriage for 20 years, meaning gay couples can have a ceremony at All Saints without the legal status conferred during ceremonies for straight couples.

"I do think it's important for kids to have role models in both the male and female roles, but my real-life experience is that same-sex couples are just as capable of bringing up healthy, whole children as (heterosexual) couples," said Russell.

As a staunch opponent of Prop. 8 during the 2008 election, Russell performed 46 same-sex ceremonies--including the legalities--between May 16 and election day, Nov. 8. Since the proposition went into effect, All Saints has ceased conferring legal status on heterosexual couples because, as Russell put it, "We will not participate in discrimination."

A church attorney also filed a friend-of-the-court brief in the Perry vs. Schwarzenegger trial on Feb. 3, claiming that the constitutional language added by Prop. 8 hinders the religious freedom of churches to decide who may marry within their walls.

"As a priest and pastor, I think the most important thing is the values that make up a family," Russell said. "I do believe the values ... transcend our gender."

Morse, who holds a Ph.D. in economics and spent 15 years teaching at Yale and George Mason University, was an outspoken supporter of the proposition in 2008. In 2010, she is still passionate about the need for constitutional language preserving the traditional definition of marriage, and she spends her days advocating "life-long married love" through her San Diego County-based nonprofit group, called the "Ruth Institute."

Another vocal Prop. 8 supporter, Pastor Chris Clark of East Clairemont Southern Baptist Church in San Diego, said California's conservative, faith-based communities are concerned that overturning the amendment would leave children vulnerable.

"You can make the case that marriage, as an institution, has lost its unique nature," said Clark, who was one of the opinion leaders behind the Prop. 8 campaign in 2008. "We believe that every child deserves a mommy and a daddy."

Morse said Canada's move to eliminate the father's information from the birth certificate was due largely to that country's acceptance of gay marriage. Not wanting to offend same-sex couples, the government defaulted to only requiring information of the woman who had just given birth, she said.

The result is a message that dad doesn't matter, said Morse: "We absolutely should not be creating a world where we're saying, 'Fathers are disposable.' We've done too much of that already."