In the eyes of that state, yes. In the eyes of God and the Church, no. Here's the real issue: Who gets to define marriage? In the eyes of a Christian, marriage and the family can't be seen as the invention of man, as if it's some design imposed on love by cultures of the past. It's the design of God. The Church didn't create marriage, and so the Church doesn't have the right to redesign it.
If man is the creator of marriage, then whatever we want marriage to be, we can arrange that. So if a man can marry a man, why can't a man marry his cousin, his sister, his mother, a child, or even two wives? If the people are willing to marry, who are you to impose your values on them and tell them they can't?
As you see, there are no boundaries left when you make the meaning of marriage subjective. So, who is to say what marriage is? God alone has that authority. In his words, a man "leaves his father and mother and clings to his wife, and the two of them become one body" (Gen. 2:24). God's blessing is on this union alone, and he commands them to "be fertile and multiply" (Gen. 1:28).
Some people object, and compare homosexual unions to a heterosexual couple who is unable to have children. But this analogy falls short, because the reason a homosexual couple can not create life is because their bodies are not designed for that. However, a heterosexual couple who is unable to have children is only that way because something is not working naturally. Sterility is a dysfunction for heterosexuals, but is natural for the homosexual couple.
If you're looking for similarities between a heterosexual couple and homosexual couple, just look at the couple using birth control. In both cases, any sexual union is closed to the gift of life. Many people don't know this, but if a couple gets married and intends to use contraception and never have kids, the Church does not recognize their marriage as valid. If they set their wills against life, then the Church says that no marriage ever existed there. They walked into the church as two singles, and they left as two singles. In the eyes of the Church the same would go with a homosexual marriage, even if it was recognized by the state.