The reason why government is involved in marriage at all is because a man and women who create a life have an obligation to raise and support the child and not just walk away. But government otherwise has no business to get involved in two consenting adults of whatever persuasion or orrientation who decide to live together.
Joel Skousen, political scientist , makes a great point that the courts are making same-gender couples a protected group and giving them false rights. Same-gender couples should have the right to live together but the government should never force the rest of the population who doesn't agree with same-gender marriage to recognize it and serve them. Joel Skousen says a false vs. fundamental rights depends on the right having both simultaneity and being non-conflicting.
For example, people have a simultaneous right to life, but not to free medical care. Free health care would require doctors to serve people involuntarily. Medical care is a false right that does not meet the "non-conflicting" criteria. Other fundamental rights would be the right to self defence, right to possess and control acquired property, etc.
Some are of the opinion that the Utah argument that "children are best raised by both mother and fathers" is weak.However, with advanced fertility, same-gender couples are now having biological children; and not just using surrogates, but actually mixing genetic material by 2 males or 2 females.
Accordingly, the argument that children are best raised by a married mother and father is still very valid. Children's right to marriage is not just for nurture issues but also because of very important genetic issues. Same-gender couples allowed to use artificial means to procreate will be a dangerous genetic experiment that would greatly limit the child's genetic diversity and fitness.
One more point: The American Academy of Pediatrics did a study to try and determine if children raised by same-gender couples were as "well-adjusted" as children raised by traditional married couples. The study found that children raised in same-gender families were only as "well-adjusted" as those raised by heterosexual families who had been divorced. But the media consistently misrepresents the findings of this study.