Here’s an interview by National Review Online’s Kathryn Jean Lopez with Professor Robert George of Princeton on marriage:
The institution of marriage has already been deeply wounded by divorce at nearly plague levels, widespread non-marital sexual cohabitation, and other damaging factors. To redefine it out of existence in law is to make it much more difficult to restore a sound understanding of marriage on which a healthy marriage culture can be rebuilt for the good of all. It is to sacrifice the needs of the poor, who are hurt the most when a sound public understanding of marriage and sexual morality collapses. It is to give up on the truth that children need both a father and mother, and benefit from the security of their love for each other.
You can read the rest here.