In a ruling last month in the southeast region of Murcia, Judge Fernando Ferrin handed the girls over to their father's care, arguing that a homosexual environment threatened their education and upbringing, reports Reuters.   

He said a gay environment increased the "risk" that the children would also grow up homosexual.  "The mother has to choose between her daughters and the new partner," Reuters quotes Ferrin as saying in his June 6 ruling. "It is a homosexual atmosphere that harms minors and substantially increases the risk that they will turn that way too."   

The Associated Press reports that The Ferrin’s decision goes against laws brought in by the government of Socialist Prime Minister Jose Luis Rodriguez Zapatero in 2005 that allow for same-gender marriages and for same-sex couples to adopt children.   

The same judge, in a separate case, already faces a probe into attempts to block the adoption of a girl by her mother's gay partner.   

According to the AP, 15 women's and gay groups filed a complaint Monday before the General Council of the Judiciary, which oversees the judiciary in Spain. The body said it was investigating.   

The judge "can think what he likes, but he cannot dictate rules that go against the law," said Silvia Jaen, the Secretary General of the State Federation of Gays and Lesbians, told the AP.   

Gays and lesbians in Spain benefit from some of Europe's most liberal gay rights legislation following decades of repression, including imprisonment, under conservative dictator Francisco Franco.   

Homosexuality was legalized in 1979 and two years ago the Socialist government made Spain only the third country in the world to legalize gay marriage.