Couples who seek surrogacy abroad won't be able to register themselves as co-parents to their children in Italy, the country's highest court has ruled.

A gay couple from Trento who had two children in Canada with the help of an egg donor and a surrogate mother cannot both be named as the children's fathers in Italy, the Court of Cassation ruled on Wednesday.

Instead, only the children's biological father will be listed as their legal parent, while his partner will have to apply for special permission to become their adoptive father – despite the fact that both men are named on the children's Canadian birth certificates.

The ruling by Italy's top administrative court ends a long legal battle for the family, who originally won their case at Trento's Court of Appeal in February 2017 to have both partners recognized as fathers. That decision was challenged late last year by Trento's public prosecutor, the mayor of Trento, and the Ministry of the Interior led by Matteo Salvini, head of the populist League party and a vocal opponent of parenting rights for same-sex couples. The decision is intended to "protect the dignity of pregnant women and the institution of adoption", the judges wrote in their statement.

Surrogacy is illegal in Italy under all circumstances, and the court's decision potentially applies to heterosexual couples as well. Its ruling refers only to the "intended parent" – i.e. the partner who isn't biologically related to the child – without entering into matters of gender or sexual orientation.

"This is certainly positive, because it demonstrates that the legal problem did not depend on the fact that a gay couple was involved," Alexander Schuster, a lawyer who has helped represent the Trento family, told La Repubblica.