Following are a few answers  to some commonly asked questions about the definition of marriage:

What is marriage?
Marriage is the lifelong partnership of mutual and exclusive fidelity between a man and a woman ordered by its very nature to the good of the spouses and the procreation and education of children. The bond of marriage is indissoluble – that is, it lasts “until death do us part.” At the heart of married love is the total gift of self that husband and wife freely offer to each other. Because of their sexual difference, husband and wife can truly become “one flesh” and can give to each other “the reality of children, who are a living reflection of their love”.

Marriage between a baptized man and a baptized woman is asacrament. This means that the bond between husband and wife is a visible sign of the sacrificial love of Christ for his Church. As a sacrament, marriage gives spouses the grace they need to love each other generously, in imitation of Christ.

Why can’t marriage be “redefined” to include two men or two women?
The word “marriage” isn’t simply a label that can be attached to different types of relationships. Instead, “marriage” reflects a deep reality – the reality of the unique, fruitful, lifelong union that is only possible between a man and a woman. Just as oxygen and hydrogen are essential to water, sexual difference is essential to marriage. The attempt to “redefine” marriage to include two persons of the same sex denies the reality of what marriage is. It is as impossible as trying to “redefine” water to include oxygen and nitrogen.

What is sexual difference?
Sexual difference is the difference of man to woman and woman to man. It affects a person at every level of his or her existence: genetically, biologically, emotionally, psychologically, and socially. Sexual difference is an irreducible difference. It is unlike any other difference we experience, because it – and only it – allows for the total personal union between husband and wife that is at the heart of marriage. The difference between men and women is for the sake of their union with each other. It is what makes spousal union possible.

Isn’t marriage just about love and commitment between two people?
Of course love and commitment are important for marriage – as they are for many relationships. But marriage is unique because the commitment it calls for is better described as communion, where “the two become one flesh” (Gen 2:24). Only a man and a woman in marriage can become a “one flesh” communion. The unity of husband and wife is so intimate that from it can come a “third,” the child – a new life to be welcomed and raised in love. No other relationship, no matter how loving or committed, can have this unique form of commitment – communion – that exists in marriage, between a husband and a wife.

What’s the difference between a husband and wife who can’t have children, and two persons of the same sex, who also can’t have children?
Only a man and a woman, as husband and wife, can enter into the two-in-one-flesh communion of persons. Only a man and a woman are able to conceive a child through each other. That is to say, only a man and a woman can be joined so intimately that their bodies work together in the common task of procreation. Even when a husband and wife do not in fact conceive a child (due to infertility, age, and so on), their sexual acts are still the kind of acts by which children are naturally conceived. In contrast, two persons of the same sex may be perfectly healthy, but will never be able to enter a one-flesh communion and thus unite in such a way that a child is conceived.

Why is a child meant to have both a father and a mother?
The fact is, every single child, without exception, does have a mother and a father. Sexual difference between a husband and wife is necessary to conceive a child. But its importance does not end there. Men and women bring unique gifts to the shared task of parenting, that is, of fathering and mothering. Only a woman can be a mother. Only a man can be a father. Each contributes in a distinct and unique way to the formation of children, helping them to understand their identity as male or female. Respecting a child’s dignity means affirming his or her need for – and right to – a mother and a father.

What about single parents? These families lack a father or a mother, just like households headed by two men or two women.
A child is meant to be raised by his or her own, married father and mother. But there are times when, due to family tragedies or other unfortunate circumstances, this ideal cannot be realized. The Church acknowledges the difficulties faced by single parents and seeks to support them in their often heroic response to meet the needs of their children. There is a big difference, however, between dealing with the unintended reality of single parenthood and approving the formation of “alternative families” that deliberately deprive a child of a father or a mother, such as arrangements headed by two men or two women. Undesired single parenthood can still witness to the importance of sexual difference by acknowledging the challenges faced by single parents and their children due to the lack of a father or mother. In contrast, arrangements of two men or two women are incapable of such witness and present motherhood and fatherhood as disposable. These arrangements of themselves contradict the conjugal and generative reality of marriage and are never acceptable. Children deserve to have their need for a father and a mother respected and protected in law.

Reprinted with permission from the ©US Catholic Bishops Conference: CommDept@usccb.org

More detailed information available at: http://usccb.org/issues-and-action/marriage-and-family/marriage/promotion-and-defense-of-marriage/frequently-asked-questions-on-defense-of-marriage.cfm#m3