What the NY Court actually did was kick the issue over to the Legislature:

First, the Legislature could rationally decide that, for the welfare of children, it is more important to promote stability, and to avoid instability, in opposite-sex than in same-sex relationships. Heterosexual intercourse has a natural tendency to lead to the birth of children; homosexual intercourse does not. Despite the advances of science, it remains true that the vast majority of children are born as a result of a sexual relationship between a man and a woman, and the Legislature could find that this will continue to be true. The Legislature could also find that such relationships are all too often casual or temporary. It could find that an important function of marriage is to create more stability and permanence in the relationships that cause children to be born. It thus could choose to offer an inducement — in the form of marriage and its attendant benefits — to opposite-sex couples who make a solemn, long-term commitment to each other.

The Legislature could find that this rationale for marriage does not apply with comparable force to same-sex couples. These couples can become parents by adoption, or by artificial insemination or other technological marvels, but they do not become parents as a result of accident or impulse. The Legislature could find that unstable relationships between people of the opposite sex present a greater danger that children will be born into or grow up in unstable homes than is the case with same-sex couples, and thus that promoting stability in opposite sex relationships will help children more. This is one reason why the Legislature could rationally offer the benefits of marriage to opposite-sex couples only.

There is a second reason: The Legislature could rationally believe that it is better, other things being equal, for children to grow up with both a mother and a father. Intuition and experience suggest that a child benefits from having before his or her eyes, every day, living models of what both a man and a woman are like. It is obvious that there are exceptions to this general rule — some children who never know their fathers, or their mothers, do far better than some who grow up with parents of both sexes — but the Legislature could find that the general rule will usually hold.

Plaintiffs, and amici supporting them, argue that the proposition asserted is simply untrue: that a home with two parents of different sexes has no advantage, from the point of view of raising children, over a home with two parents of the same sex. Perhaps they are right, but the Legislature could rationally think otherwise. * * *

Plaintiffs seem to assume that they have demonstrated the irrationality of the view that opposite-sex marriages offer advantages to children by showing there is no scientific evidence to support it. Even assuming no such evidence exists, this reasoning is flawed. In the absence of conclusive scientific evidence, the Legislature could rationally proceed on the common sense premise that children will do best with a mother and father in the home. (See Goodridge, 798 NE2d at 979-980 [Sosman, J., dissenting].) And a legislature proceeding on that premise could rationally decide to offer a special inducement, the legal recognition of marriage, to encourage the formation of opposite sex households.

In sum, there are rational grounds on which the Legislature could choose to restrict marriage to couples of opposite sex. Plaintiffs have not persuaded us that this long accepted restriction is a wholly irrational one, based solely on
ignorance and prejudice against homosexuals. This is the question on which these cases turn. If we were convinced that the restriction plaintiffs attack were founded on nothing but prejudice — if we agreed with the plaintiffs that it is comparable to the restriction in Loving v Virginia (388 US 1 [1967]), a prohibition on interracial marriage that was plainly “designed to maintain White Supremacy” (id. at 11) — we would hold it invalid, no matter how long its history. As the dissent points out, a long and shameful history of racism lay behind the kind of statute invalidated in Loving.

But the historical background of Loving is different from the history underlying this case. Racism has been recognized for centuries — at first by a few people, and later by many more — as a revolting moral evil. This country fought a civil war to eliminate racism’s worst manifestation, slavery, and passed three constitutional amendments to eliminate that curse and its vestiges. Loving was part of the civil rights revolution of the 1950’s and 1960’s, the triumph of a cause for which many heroes and many ordinary people had struggled since our nation began.

It is true that there has been serious injustice in the treatment of homosexuals also, a wrong that has been widely recognized only in the relatively recent past, and one our Legislature tried to address when it enacted the Sexual Orientation Non-Discrimination Act four years ago (L 2002, ch 2). But the traditional definition of marriage is not merely a byproduct of historical injustice. Its history is of a different kind.

The idea that same-sex marriage is even possible is a relatively new one. Until a few decades ago, it was an accepted truth for almost everyone who ever lived, in any society in which marriage existed, that there could be marriages only between participants of different sex. A court should not lightly conclude that everyone who held this belief was irrational, ignorant or bigoted. We do not so conclude.

The Court held that the New York Constitution is silent on the issue of same-sex marriage, and that denying gays the right to marry does not violate the state constitution’s Due Process Clause ("Nop person shall be deprived of life, liberty, or property without due process of law"), nor the Equal Protection Clause ("No Person shall be denied the equal protection of laws of this State or any subdivision thereof").

The court’s reasoning is tortured, in my view.  For example, under New York intestate succession laws, if a husband dies without a will, his estate goes to his wife.  She is protected by that law.  The New York law designed to protect the property of the deceased and keep it with his loved ones.

But if gay people can’t get married, then they do not have "equal protection" under the intestate succession law.  The deceased’s estate could go to someone else, or to the state itself.

Apart from that, not allowing gay marraige is just plain discriminatory.  It’s treating a siginficant subset of people differently based solely on their sexual preference.

But this is just one step in a larger struggle, and being New York, I am confident that the legislature will do the right thing.

(H/T: Orin Kerr)