A ban on gay and unmarried couples applying to adopt children in Northern Ireland has been removed.
They may now apply in the same way as heterosexual couples.
Health Minister Edwin Poots had tried to challenge an appeal court decision to extend adoption rights to gay couples.
However, the Supreme Court said the Department of Health's argument for appeal did not meet the criteria.
Previously, a single gay or lesbian person could adopt children in Northern Ireland, but a couple in a civil partnership could not.
In June, the Court of Appeal ruled that the ban based on relationship status was held to discriminate against those in civil partnerships and to breach their human rights.
Northern Ireland was the only part of the United Kingdom where that policy existed.
Now, the law in Northern Ireland is in line with the rest of the UK.
A Department of Health spokesperson said: "Following the Court of Appeal judgement in June 2013, unmarried couples, including same sex couples, and those in a civil partnership may apply to adopt.
"The final decision regarding the granting of an adoption order will lie with the court."
The spokesperson said that the Northern Ireland Human Rights Commission had initiated judicial review proceedings on adoption law and guidance in early 2011.
The Department of Health appealed against the judicial review judgment handed down in October 2012.
The Court of Appeal judgment was handed down in June 2013 and an application to the United Kingdom Supreme Court seeking leave to appeal against the Court of Appeal judgment was made by the Department of Health in September 2013.