Archbishop John Myers of Newark, N.J., says that the sexual complementarity allowing for the possibility of children is vital to marriage and a reason why the fundamental institution cannot be redefined.

“Marriage is not mere sexual-romantic domestic partnership,” the archbishop said in a Sept. 14 pastoral message. “It is, at its very foundation, a one-flesh union.”

The sexual union of a man and woman renders them truly “one flesh” and allows for the possibility of new life, he said.

While not every instance of such a union results in a new life, it is this type of union alone that leads to children, he noted, adding that same-sex couples “cannot participate in reproductive type acts” because they lack the necessary sexual complementarity.

The life-giving potential of the sexual union between a man and a woman is what leads the state to recognize it, the archbishop said, observing that the state does not have an interest in recognizing and regulating deep friendships.

He noted that that while friends, teammates and colleagues engage in bodily activities together such as eating meals, playing sports and performing manual labor, these activities do not constitute a marriage.

Rather, he explained, “everyone recognizes that marriage involves a sexual component, which these other physical experiences lack.”

“The state does not and should not regulate our ordinary friendships or voluntary associations because, important as they are, they do not affect the political common good in direct and structured ways,” he said.

However, the union that brings new life into the world presents a vital interest to the state, he continued. Healthy families are critical to a strong society, and the state therefore has an interest in promoting “the best possible environment for the healthy development of children.”

Archbishop Myers pointed to a study by Child Trends, a non-partisan research institute, indicating that children do best when raised by their married, biological parents.

He explained that these findings align with Church teaching about marriage, which says it is “the fundamental building block of every society,” which provides the “ideal context” for children to be raised.

These truths about the nature, purpose and meaning of marriage are not only found in Scripture, Tradition and the magisterium, but can also “be known through reason, unaided by revelation,” the archbishop noted.

Marriage is “part of natural law,” rooted in the biological nature of humanity and existing prior to the state, which does not have the authority to redefine it, he explained.

Since its founding, the United States has based its civil law on the universal laws of nature, he said, observing that the nation’s failures “have come when we have ignored the self-evident truths of right reason.”

Therefore, he said, the attempt to radically redefine marriage is not a modern-day civil-rights campaign, since it is based upon denying the natural law.

While the Church calls us to love all people and to treat those with same-sex attraction “with respect, compassion and sensitivity,” it also recognizes marriage’s unique connection to the procreation and upbringing of children, which has been acknowledged “by all the major cultures of the world,” the archbishop said.

He urged those who are not in communion with Church teaching on marriage to sincerely “re-examine their consciences,” adding that, as with other grave matters of faith, those who do not assent to or live out the Church’s teaching should refrain from receiving Communion.

Archbishop Myers explained that a redefinition of marriage would be harmful to society because it would further distort people’s understandings of the definition of marriage, teaching that the redefinition effort is essentially “about adult emotional and physical gratification” and enshrining “in law a non-optimal way to raise children as equivalent to that which is best.”

Redefining marriage would also “seriously undermine religious freedom,” he warned.

He pointed to examples of those who defend marriage being accused of bigotry and forced to leave the adoption business because of their views, as well as legal and civil actions taken against hotel managers, owners of reception halls and photographers who object to affirming same-sex “marriage.”

“How long would the state permit churches, schools or parents to teach their children that homosexual activity is contrary to the natural law if homosexual marriage were a civil right?” he asked, noting that “hate speech” laws in other democracies have already been used to arrest clerics who teach the Bible’s message on marriage.

As both believers and citizens of the United States, he said, bearing the responsibility to help promote the common good, Catholics “must exercise their right to be heard in the public square by defending marriage. ”