Closing arguments in the landmark trial challenging California's ban on same-sex marriage will begin Wednesday.

The trial challenges the constitutionality of Proposition 8, California's voter-backed measure to end same-sex marriage in the state.

The ruling is likely to be appealed no matter the outcome.

Jordan Lorence of the Alliance Defense Fund told CBN News there's a possibility the case could end up in the Supreme Court.

"I think that the legal theories are so far-fetched that they should be rejected by the lower court, but if it gets up the Supreme Court, there is a possibility of an adverse ruling," he explained. "And it would jeopardize all of the 30 marriage amendments on the books and in state constitutions around the country... [the] 14 or so states that define marriage as one man and one woman [in] their state statutes."

"This would all be vulnerable to attack under the federal constitution," Lorence added.

The attorneys defending Prop 8 are basing much of their case on the fact that same-sex couples can never offer a child both a mother and a father.