Germany's highest court ruled on Tuesday that gays in a civil partnership should be allowed to adopt their partners' adopted children, saying they can bring them up as well as couples in a traditional marriage.
The Constitutional Court in Karlsruhe, western Germany, ruled that an existing law forbidding gays and lesbians from adopting their partners' already adopted children went against the country's basic law or constitution.
Gay couples are still forbidden from adopting children in Germany.
"The protective relationship of a civil partnership can foster the upbringing of children just as well as in a marriage," the judges said in their ruling.
The German Family Association (DFV) had argued that a child could be harmed by being brought up by same-sex partners.
But expert studies commissioned by the court determined that adoption "creates a stabilising psychological effect" for the children concerned.
The court was ruling on two specific cases.
A lesbian woman had adopted a Bulgarian-born child and her partner, who was involved in the daily upbringing of the child, was forbidden from formally adopting it.
In another case, a gay man had been prevented from adopting his partner's Romanian-born adopted child.
The German Gays and Lesbians Association (LSVD) welcomed the ruling and called on Chancellor Angela Merkel to end what it called a "policy of discrimination against life partners."
"After five rulings against discrimination of life partners, even the most ardent hardliner must realise that such a policy is illegal," said LSVD spokeswoman Renate Rampf.
Germany introduced registered partnerships of same-sex couples in 2001 granting them similar rights to those of married couples, apart from in tax matters and adoption.