Gary Buseck, legal director at the gay rights group Lambda Legal
Marriage in America is of tremendous social and legal importance. It is at the center of how we structure our families; it is the primary way that people acknowledge, and accept responsibility for, the person they have chosen, above all others, to be with for the rest of their lives; and it is the legal institution through which government supports America's couples and families. Marriage is a core institution in our society - the "gold standard" for couples.

Same-sex couples seek to enter the institution of marriage for the same mix of reason as any other couples, and they should be allowed to do so without others fearing harm to the institution. The institution of marriage is only as strong as those who are in it, and it is weakened, by definition, when it arbitrarily excludes any class of couples. Some of the couples Lambda Legal represents in lawsuits seeking marriage equality have been together for nearly 30 years. Phyllis Lyon and Del Martin, the lesbian couple who were the first to marry in San Francisco, have been together for 51 years. These couples need and want access to marriage.

In addition, for same-sex couples with children, marriage provides a more secure structure of support for children. Contrary to the rhetoric put forth by opponents of marriage equality, barring gay men and lesbians from marrying won't make a mom and a dad magically appear for kids raised in same-sex households. What it means is that those children won't have the benefit of the protections marriage provides through their parents.

Peter Sprigg, director of marriage and family studies at the Family Research Council
Marriage is the most important social act and involves much more than just the married couple. A new home is formed when a couple marries, are open to the creation of new life. Marriage also has beneficial social and health effects for adults and children, and these gifts benefit the community and the whole society.

Among marriage's benefits to society is an increased respect for and protection of human life, since married women are less likely to abort their children than are unmarried women. Married-parent families contribute to safer and better communities with less substance abuse and crime among young people, as well as less poverty and welfare dependency.

The legalization of homosexual civil "marriages" (which are intrinsically infertile) would extend and reinforce harmful social trends that have already divided sexual relations, childbearing, childrearing, and marriage. The separation of sexual relations from marriage has led to an epidemic of sexually transmitted diseases; the separation of childbearing from marriage has led to an explosion of out-of-wedlock births; and the separation of childrearing from marriage has led to the growth of single-parent households. Anthropologist Stanley Kurtz has demonstrated that legal recognition of homosexual unions in Scandinavia has reduced both the percentage of the population that marries and the percentage of children being raised by a married couple.

In addition, including homosexual relationships within the ideal of "marriage" would inevitably change social norms surrounding the institution. Research has shown that homosexual men, in particular, have many more sexual partners outside the primary relationship and have much shorter relationships than heterosexual marriages. This example would undermine all of society's commitment to sexual fidelity and lifelong commitment in marriage.

Andrew Koppelman, professor of law and political science at Northwestern University
Marriage is important in American society for both expressive and utilitarian reasons, and the term "marriage" has both dimensions. We are really having two debates at once. The first concerns what relationships to honor. The second concerns which relationships ought to have legal consequences.

The first debate turns on whether same-sex relationships as such are morally equal to heterosexual relationships, or whether, on the contrary, heterosexual relationships partake of a good that homosexual relationships cannot possibly share. The answer turns on ultimate value judgments, about which there is not likely to be agreement any time soon. The second debate concerns what relationships between persons ought to be given legal recognition. Here we face the more mundane question of how resources should be allocated and unfair disruption of people's lives prevented. Like it or not, households, of whatever kind, and relationships of dependency exist, and legal recognition of those relationships is hard to mimic with private contracts. When your spouse is injured and you're rushing to the emergency room, you probably won't be able to stop by your safe deposit box to pick up your power of attorney.

Whatever you think about the value question, including gay people in marriage would strengthen the institution in the same way that any institution is strengthened if more people participate in it.

Thomas Kohler, professor at Boston College Law School
In one sense, marriage is as important to society today as it ever has been. The social science evidence collected by our contemporaries bears out what our grandparents told us. Children do best -- on nearly every measure -- when raised by their biological parents united to one another in an intact marriage. Likewise, couples in an intact marriage do better than those who either are single or divorced. As a group, they enjoy better health, live longer, build more wealth, and suffer lower rates of illness, etc., than do otherwise similar single or divorced individuals. Marriage is a social good, the benefits of which, both quantifiable and otherwise, have been recognized by every society throughout human history. While it has its private aspects, marriage also is a public institution, which traditionally has been supported both by social norms and special legal recognition.

Despite all this, there is no denying that marriage, like our other institutions, has come under considerable stress. While the number of divorces has declined over the past decade or so, the rates nevertheless remain high. Moreover, the rate of marriages has declined to historically low levels. As a society, we seem completely to have forgotten what the institution means.

Marriage is a unique institution that acknowledges the complementary differences between men and women and that recognizes the need of children for both a father and a mother. No other relationship between or among people, regardless of how noble, performs the quite same functions. The culture of divorce has hurt marriage as an institution far more than anything else in this society.

Brad Sears, executive director of the Williams Project on Sexual Orientation Law at UCLA
Marriage remains one of the fundamental building blocks of society, both in the United States and around the world. Marriage is a set of legal and economic rights that supports families in taking care of each other -- spouses caring for one another, parents caring for children, and children eventually caring for parents. Gay marriage strengthens society and the institution of marriage by allowing more people to participate in the institution and receive its benefits. Census and other data show that gay couples and the children of gay couples are just as much in need of the support that marriage provides, if not more, as straight couples. Hundreds of thousands of children, of every race and ethnicity, and in every region of the country, are being raised by gay couples. These families need the strength and support that marriage provides.

Dwight Duncan, associate professor of law at Southern New England School of Law
Marriage is important today, as it always has been, principally because it is society's preferred vehicle for bringing children into the world and providing them with both a mother and a father. But didn't marriage as a civil institution long ago sever its link to procreation and the raising of children, given the widespread acceptance of contraception, abortion, divorce, in vitro fertilization and single parenting?

Well, marriage still matters because children still matter. Children, even test-tube babies, can only come about through the union of male and female. Common sense, as well as the documented bad effects of fatherlessness, says that children are best raised by a mother and a father united in marriage. Same-sex couplings cannot produce children, nor can they provide children with both a mother and a father. This is a matter of physiology. It is not bias to notice that there is a difference in meaning between reproductive intercourse, the quintessential "fact of life" where procreation is possible, and other sexual encounters for pleasure. Society has a huge stake in the former; no stake in the latter.

After all, one doesn't need a license from the government to be friends with someone, or even to live together. You don't need government permission to break off a friendship, but you do to get a divorce. The link to the procreation and education of children is why marriage, uniquely among types of friendship, is given public recognition, and freighted with special rights and duties. Extending marriage to homosexuals would completely sever the already tenuous link between marriage, procreation, and mother-father parenting.