Should the moral conviction that marriage is a lifelong relationship between one man and one woman be put into the Constitution? This is a question faced by evangelical Christians, who overwhelmingly agree that this is God's desire for marriage.

First, we need to be clear that all human beings are created in the image of God, and we love, welcome and respect them as God's created beings. Our call as Christians is to love all people no matter if their marriages haven't turned out to be lifelong, or if they choose to live in alternative relationships, or if they have same-sex desires. The Bible calls Christians to love all people as together we seek to rediscover God's vision for healthy and sustainable relationships.

Within evangelical Christianity, we often have failed to reach this vision. Yet we still aspire to God's ideas, because we believe sex and marriage are good gifts from God intended to bless married couples, to serve the good of children and to build stronger communities.

But the marriage amendment is more than putting moral convictions into the Constitution. All laws are based on some conception of what is good for the public. Voting "yes" on the marriage amendment reflects a belief that it will enhance the public good to define marriage to be one man and one woman.

Minnesota's Constitution has been amended to define important public values before -- for example, that "hunting and fishing and the taking of game and fish are a valued part of our heritage" to be preserved for the people and managed by law.

In other words, we Minnesotans believed that hunting and fishing are such important values that we chose to include them in our state Constitution and required laws regulating these activities. Marriage has much greater significance, and we believe it, too, should be defined and protected by our Constitution.

The public benefit of marriage is clearly supported by social-science research. In the 2011 report "Why Marriage Matters: Thirty Conclusions from the Social Sciences," 18 scholars, a majority of them secular researchers at public universities, summarize the literature by saying that "marriage is an important social good associated with an impressively broad array of positive outcomes for children and adults alike." These include reducing child poverty, strengthening the child-parent bond, and improving health and educational outcomes.

Fatherhood in particular has positive effects on child outcomes. The National Fatherhood Initiative has long lists of research results that show that children raised in stable homes with a married father in the household have better emotional health, fewer behavioral problems, and lower teen pregnancy and sexual activity rates. These are just some of the benefits of having a married father in a child's life.

Mothers are by nature more closely tied to their children and play a distinctive role in their development. Mothers and fathers love and interact with their children in distinct and unique ways, and both are important to the well-being of children; neither role is replaceable. Marriage is what attaches fathers and mothers to their children. The definition of marriage should support this fact.

In "Why Marriage Matters," researchers conclude that "whether American society succeeds or fails in building a healthy marriage culture is clearly a matter of legitimate public concern."

Marriage is an important social institution, and healthy marriages can provide better outcomes for children, women and men. How you vote on the marriage amendment is an important public-policy decision that impacts children's lives, our schools, communities and social services.

As the evangelical network representing nine evangelical denominations and 160 churches, Transform Minnesota believes that evangelical Christians should vote "yes" for the marriage amendment, certainly because our faith informs what we believe marriage to be, but specifically because the evidence shows us that marriage is a public good of such great importance that it deserves to be defined in our Constitution. And as you vote, make a commitment to love, welcome and respect all people as human beings made in the image of God.

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Raymond C. Kuntz is board chair and Carl H. Nelson is president and CEO of the evangelical association Transform Minnesota. To read more marriage amendment commentaries, go here.