PORTLAND – The state’s highest court on Thursday overturned a lower court decision, opening the door for a lesbian couple to adopt two siblings who have been in their care for six years.

The Maine Supreme Judicial Court unanimously ruled that state law does not preclude Ann Courtney and Marilyn Kirby of Portland from adopting the children, a 10-year-old girl and her 6-year-old brother.

Courtney and Kirby became the children’s foster parents in 2001; last year they filed petitions with the Cumberland County Probate Court to adopt.

Their petitions were rejected, but the supreme court concluded state law does not prohibit two unmarried people from together adopting a child. As a result of the ruling, the matter will be sent back to probate court for further proceedings.

“We love these kids, and their well-being means everything to us,” Courtney said. “Our daughter and son can now know that we are a family, and we’ll always be a family.”

Courtney and Kirby, who were not identified in court documents but made their names known after the decision, became foster parents after the children – then 4 years and 4 months old – were removed from the care of their biological parents.

The children have been diagnosed with post-traumatic stress disorder, reactive attachment disorder, and attention deficit and hyperactivity disorder.

Courtney, who is an attorney, and Kirby, a counselor, later filed two petitions with the probate court seeking to jointly adopt the children. The court, however, denied the petitions, saying it lacked jurisdiction.

Courtney and Kirby then appealed to the supreme court. Maine Attorney General Steven Rowe also filed a friend of the court brief arguing that prohibiting the adoption would be counter to Maine’s Adoption Act.

The supreme court said the probate court has jurisdiction, and that state law allows for an unmarried couple – not just married couples or one unmarried person – to adopt. The overriding objective of the law is to protect the children’s welfare, the justices ruled.

A joint adoption assures the children’s continued relationship with a surviving parent in case of a death, and also enables them to be eligible for a variety of public and private benefits ranging from Social Security to health insurance and family leave, the justices wrote.

“Most importantly, a joint adoption affords the adopted children the love, nurturing and support of not one, but two parents,” Justice Jon Levy wrote in the ruling.

Mary Bonauto, an attorney with Gay & Lesbian Advocates & Defenders who represented Courtney and Kirby, said state adoption workers, the children’s guardian and a social worker who completed a home study all agreed that Courtney and Kirby would make good parents.

“This decision is in the best interest of the children, who have flourished under Ann and Marilyn’s care,” Bonauto said.

Adoptions by unmarried couples are expressly permitted in a dozen other states, including Connecticut, Vermont and Massachusetts in New England, according to Gay & Lesbian Advocates & Defenders.