Advocates of gay marriage have lost court battles in two of the largest US states, New York and Georgia.
Kathy Burke (left) said it was a sad day for New York families
New York's Court of Appeals ruled the state constitution does not grant a right to gay marriage, but left open the option for a change in the law.
In Georgia, the Supreme Court rejected the argument that the state ban on gay marriage had been improperly passed.
American proponents of gay marriage have had success with court battles only in the state of Massachusetts.
The New York case combined four different suits brought by more than 40 same-sex couples who had spent two years fighting their case through the New York courts.
Three judges ruled that the state constitution did not require New York to recognise same-sex marriages.
A fourth judge concurred, though she added that it may be time "for the Legislature to address the needs of same-sex couples and their families".
Two judges wrote a heartfelt dissent, and one declined to participate in the case because his daughter has lobbied for gay marriage in California.
The ruling is the end of the line for this particular case, which the gay marriage advocates fought only on state law, not federal law.
Gov George Pataki and Attorney General Eliot Spitzer - a leading candidate to be the next governor - had argued that lawmakers could reasonably believe marriage should be limited to one man and one woman.
Only Massachusetts fully recognises same-sex marriages
Kathy Burke, one of the plaintiffs, said it was "a sad day for New York families", the Associated Press reported.
Another plaintiff, Regina Cicchetti, said she and Susan Zimmer, her partner of 36 years, had not given up.
"We're in this for the long haul. If we can't get it done for us, we'll get it done for the people behind us," AP quoted her as saying.
Georgia's Supreme Court decided its case on narrower grounds than New York's - where the plaintiffs claimed the ban on gay marriage was discriminatory.
The Georgia case concerned whether the state ban on gay marriage was imposed properly when it was approved by more than three in four voters state-wide in 2004.
A lower court ruled the ballot was improper, but the Supreme Court disagreed, thus reinstating the ban.