Economist: Evidence backing gay marriage is in

Same-sex couples in some parts of the United States have been able to wed for long enough to conclude that expanding gay marriage to other states would not undermine traditional marriages, a University of Massachusetts economist testified during a trial on California's same-sex marriage ban.

Lee Badgett's testimony Tuesday finished off the sixth day in the historic trial, the first in a federal court to examine whether prohibiting gays and lesbians from marrying violates their constitutional rights.

Badgett, who also directs research for a gay-related think tank at the University of California, Los Angeles, took the witness stand on behalf of two same-sex couples suing to overturn Proposition 8, the state's voter-approved ban. She cited statistics from Massachusetts, which has allowed gay couples to marry since 2004, showing that marriage and divorce rates for straight couples have not been affected.

"I don't think we need to wait any longer to see what the impact will be. I think we know," Badgett said. "Everything I've looked at leads me to the conclusion that there is no impact."

Charles Cooper, a lawyer for Proposition 8's sponsors, spent several hours with Badgett trying to demonstrate that traditional male-female marriages suffered after same-sex marriages became legal in the Netherlands in 2001. During her cross-examination, he introduced a number of charts showing divorce and single parenthood rates increased while marriage rates fell in the that country.

Badgett rejected the comparison, however, noting those trends were firmly established long before gay couples won the right to wed in the Netherlands and were unrelated to same-sex marriage.

In other testimony, San Diego Mayor Jerry Sanders recalled the "defining moment" of his personal and political life when he decided that denying gays and lesbians the right to wed was discriminatory. The change of heart came about in part after he learned his daughter was a lesbian in a committed relationship.

"I had been prejudiced," Sanders said. "I was saying one group of people did not deserve the same respect, did not deserve the same symbolism of marriage and I was saying their marriages were less important than those of heterosexuals."

Plaintiffs' lawyers are expected to wrap up their case this week. They are scheduled to present testimony Wednesday from a gay man who was forced to undergo so-called "conversion therapy." Ryan Kendall's testimony is being used to argue that sexual orientation is not a choice and usually cannot be changed.