Archbishop Salvatore Cordileone of San Francisco on Friday lashed out at the state of Rhode Island over a newly signed law that allows same-sex couples to legally marry.

Cordileone, the chairman of the U.S. Conference of Catholic Bishops' Subcommittee for the Promotion and Defense of Marriage, described the law as "a serious injustice." He suggested that marriage equality for gay and lesbian couples would be harmful to children, who deserve to have both a mother and father.

"Marriage is the only institution that unites a man and a woman to each other and to any child conceived of their union," Cordileone said. "While those making great sacrifices to raise their children in less than ideal circumstances need and deserve our love and support, we cannot claim to have a just society if we do not look out for the most vulnerable among us: children.

"That means preserving in the law the principle that every child deserves a mother and father united in marriage. That means supporting in our institutions and in our culture the true and unique meaning of marriage."

Cordileone is not the only prominent Catholic official to have condemned the new law.

After Rhode Island became the tenth state to legalize same-sex marriage on Thursday, Bishop of Providence Thomas Tobin warned, "Catholics should examine their consciences very carefully before deciding whether or not to endorse same-sex relationships or attend same-sex ceremonies, realizing that to do so might harm their relationship with God and cause significant scandal to others."