Opponents of a gay marriage bill in Britain argue that marriage is “great for kids” when their parents are heterosexual.

The bill, which would make Britain the 15th nation to legalize marriage rights for gay and lesbian couples, cleared a second reading in the House of Lords earlier this month, leaving little doubt that it will become law.

And while the Church of England appears prepared to accept the measure's imminent passage, other opposition groups have continued the fight.

(Related: Church of England ready to accept gay marriage.)

In a nearly 2-minute video released last week by the Coalition for Marriage, Dr. Sharon James argued that marriage should remain a heterosexual union and is “great for kids.”

“Up until now the government has regulated marriage because marriage is a public institution intended to provide a secure environment for the raising of children,” James says. “The law on adultery discourages husbands from fathering children with women other than their wives. Marriage as an institution exists to maximize the likelihood that men commit to the women they are sleeping with and the children they help to create.”

“Redefining marriage would send out a signal that fathers are optional. It would affect all of us by weakening the status of traditional marriage, which provides the most stable environment for raising children.”

“Marriage is great for kids. Marriage works,” James adds. (The video is embedded on this page. Visit our video library for videos.)

According to U.S. Census data, an estimated one-quarter of all same-sex households are raising children.