Campolo, Same-Sex Marriage, and Procreation

This morning I posted this piece on procreation and same-sex marriage in response to a new NYT article. Now this statement from Tony Campolo affirming same-sex marriage shows up in my Twitter feed; thanks to Ed Stetzer for the link. Here's the paragraph I want to comment on in Campolo's post:

For me, the most important part of that process was answering a more fundamental question: What is the point of marriage in the first place? For some Christians, in a tradition that traces back to St. Augustine, the sole purpose of marriage is procreation, which obviously negates the legitimacy of same-sex unions. Others of us, however, recognize a more spiritual dimension of marriage, which is of supreme importance. We believe that God intends married partners to help actualize in each other the “fruits of the spirit,” which are love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control, often citing the Apostle Paul’s comparison of marriage to Christ’s sanctifying relationship with the Church. This doesn’t mean that unmarried people cannot achieve the highest levels of spiritual actualization – our Savior himself was single, after all – but only that the institution of marriage should always be primarily about spiritual growth.

The essential point Campolo makes is that marriage is primarily about spiritual growth. Since same-sex marriages evidence that same type of spiritual growth, they are legitimate. What he doesn't explain is how procreation can now be entirely pushed aside. Based on the entirety of the biblical evidence, I don't think it can be. For example, after Paul extols the spiritual value of marriage, he immediately speaks to how parents and children are to live out their faith with each other (Eph 6:1–4). That's a natural progression from marriage to children, something Paul saw as fundamental to the order of creation. Witness his argument in 1 Tim 2:15: As difficult as it is to determine all the nuances of this verse, referentially at a minimum it involves a woman giving birth to a child, something that does not occur without outside intervention in a same-sex marriage. Campolo and others who claim to be biblical cannot simply reject the procreation argument out of hand to justify same-sex marriage. That doesn't do justice to the biblical text.