Marriage is one of the few human universals that transcend culture, religion, and history. 

Marriage existed before government, and even before established religion.  From the beginning of human history the two great halves of humanity, male and female, have joined themselves together for their own good and for the common good, namely, the procreation and education of children destined to be healthy and productive new members of the community.  Even recognizing the diverse expressions of marriage known throughout history (arranged marriage, romantic marriage and marriage of convenience to name a few), it is remarkable what these marriages have in common: a community-sanctioned, life-giving union of a man and a woman for reciprocal good. 

For the first time in human history, same-sex couples are demanding the right to marry.  How should we, as faithful Catholics, respond to this demand?  How do we respond to one of the common questions regarding same-sex “marriage” - If two people love and commit themselves to each other, what is wrong with same-sex “marriage”?

"Let us make man in our own image, after our likeness, male and female he created them and bless them, saying ‘be fruitful and multiply.’" (Gen. 1:27)

To be sure, the case against same-sex “marriage” can be, and has been, made without religious, biblical or theological arguments (see www.marriagedebate.org).  But as believing Catholics, we hold in our heads and hearts the fundamental understanding of why same-sex unions are not equal to or the same as “marriage.”

Essentially, the case against same-sex “marriage” leads us to examine the meaning of love.  An understanding of authentic love does not simply tell us that same-sex “marriage” is not allowed, but not possible.  Certainly sincere same-sex “marriage” advocates, and perhaps some of us who know them, declare that this new movement is, in fact, rooted in love.  This apparent contradiction, though, lies in a limited understanding of love.  Based on the fullest understanding of conjugal love, we understand and believe that marriage, in the natural law, requires sexual complementarity, that is, the union of male and female. 

We are all called to love. It is the great human vocation given by God, who is love. In the English language, though, we have this one word – love – to describe everything from our favorite sports team to God himself.  Of course we mean different things when we say “I love Pepsi," “I love my mom,” “I love my wife” or “I love my kids,” but those distinctions are often lost when they are needed most. 
Ancient Greek, the root of Western languages, had at least four different words for love that have been redeemed and infused by the Christian faith. Storge describes the duty of family bonds, phileo the love of friendship, eros the passion of romantic love and sexual attraction, and agape as the supreme pledge of total reciprocal self-gift.  All these loves are good because they are given to us by God.  Yet there are distinct differences to each of these.  Marriage brings together all of these loves as conjugal love sealed by a single freely-given agape pledge.  In marriage, a man and a woman pledge to love as God loves - freely, totally, faithfully and fruitfully.  Conjugal love is the love of total personal communion.  So total, so complete is conjugal love that it demands our whole person, body and soul, as a gift given and received. 

This reciprocal self-gift is “in the image and likeness” of God himself who is an eternal exchange of love: Father, Son and Holy Spirit.            

It is gender that makes it possible for “two” to become “one”.  Our bodies as male and female express our capacity and call to enter into personal union. God made us male and female not just to be different from each other, but to be different for each other. This is no mere biology lesson seeking to explain bodily difference. Our bodies don’t define who we are – they express who we are.

Yes, we are all called to “love”. Marriage, though, requires conjugal love, and conjugal love requires sexual difference. Intimate love (phileo, friendship) between two men or two women should be praised and encouraged. However, eroticizing that friendship actually speaks loudly against authentic love in marriage.  Marriage is, in its essence, the unity of male and female for the good of one another and the good of society.  Same-sex unions cannot be “marriage,” because the partners are lacking in the innate ability to complement, or complete, one another as God intended.