Gigi Carrier Cowell (center) was adopted by her lover, Shirley Cowell (white blazer), for inheritance purposes. The longtime partners' relationship started decades before any same-sex marriage law. Both have since died, but the adoption has led to a legal complication where their $25 million will likely languish in an unclaimed fund with the state of New York. The undated photo is of Gigi with Claire Carrier and her niece and nephew. View Full Caption Facebook/Sam Carrier

NEW YORK CITY — The $25 million estate of a late lesbian model and actress may languish in permanent limbo, collecting dust in an unclaimed funds account controlled by the city — all because she was never able to legally marry her longtime partner, court documents show.

Fashion model Gigi Carrier and her wealthy socialite lover, Shirley Ione Cowell, were in a long-term romance decades before same-sex marriage was legalized.

Their relationship spanned nearly 40 years until Cowell’s death in 1997.

But despite the devoted partnership, they didn't have access to the same economic and legal benefits afforded to a husband and wife. So they improvised to ensure Cowell’s massive fortune would eventually pass onto Carrier.

In 1971, while living in Florida, Cowell, then 57, legally adopted Carrier, then 41, as her daughter.

The maneuver allowed Cowell, a singer and actress and the daughter of an oil man, to leave tens of millions of dollars in a trust to Carrier when she died.

But when Carrier died at 71 in 2009, her adoption led to an unprecedented legal quagmire — one that's stymieing her own brother from inheriting her $25 million estate.

Carrier, who lived in an $8 million apartment in the tony River House in Midtown East, didn’t leave a will or instructions on what to do with her money and assets.

New York law says that, without a will, her fortune would go to her closest kin. Carrier’s biological brother, Leonard Carrier, said that since she had no children and no living parents, that’s him.

The Office of the Manhattan Public Administrator — which handles the estates of borough residents who die without wills — has acknowledged that Leonard is her closest surviving blood relative, but said he’s disqualified from getting the money.

In a filing in Manhattan Surrogate’s Court, lawyers for the public administrator said that New York law states that when an individual is adopted and later dies without a will his or her biological parents or siblings lose the right to collect the money.

Leonard Carrier, who first challenged the public administrator’s interpretation of the law in 2009, said that he and his sister maintained a close, loving and supportive relationship with each other throughout their lives.

The retired philosophy professor said his sister and Cowell — who began their romance in 1960 — were victims of their time.

The adoption, he said, was a way to circumvent the laws of a less-accepting society — not to distance herself from her biological family.

“The adoption in this case occurred in the context of a mature, long-time, same-sex relationship,” Leonard’s lawyer, Tom Bonner, wrote in a filing in surrogate’s court in December 2014.

“Had the laws of the state of Florida in 1979 permitted the marriage of [Gigi Carrier] and Shirley Cowell, it is clear they would have married and obtained all of the legal and economic benefits of marriage.”

Leonard Carrier died in June 2014, but his wife, Claire, and their two children are continuing the fight for the money.

In a December 2014 affidavit, Claire wrote about her and her husband’s close ties with his sister. She and her husband frequently played tennis and shot pool with Gigi and Cowell when they lived in Miami Beach, in the $15 million former home of Howard Hughes.

Claire also recalled attending sing-a-longs at Gigi and Cowell’s home with famous friends like jazz chanteuse Lena Horne, legendary Broadway producer George Abbott and Met Opera soprano Eileen Farrell showing up to belt out a tune.

Gigi also lavished her brother and his wife with presents. Leonard was once given a Cartier watch while Claire often received expensive jewelry.

Gigi also handed Claire the keys to a navy blue Ford Thunderbird roadster to use. A classic car aficionado, Gigi would also take them for rides in her collection of fancy wheels, including a 1984 Aston Martin.

Claire's portrait of a close-knit family has not swayed the office of public administrator, which last fall said that if Gigi intended for Leonard and his family to receive the $25 million, then she would have made a will naming them as the beneficiaries.

Moreover, Schram, Graber and Opell, the private law firm that acts as counsel for the public administrator, said that it has determined that none of Gigi’s relatives in her adopted family qualify for her money.

State law requires that only a relative who is a cousin once removed or closer in relationship qualifies to inherit the money of someone who dies without a will.

Glenn Opell, a lawyer at Scrham, Graber and Opell, declined to comment.

Claire’s lawyer, Thomas Bonner, did not respond to a request for comment.

Surrogate’s Court Judge Rita Mella has also appointed a lawyer to act as a guardian ad litem to represent the interests of any unknown relatives who may qualify for the inheritance. That lawyer, Linda Kordes, said in a filing this February that she so far she has also not discovered any relatives who qualify.

Judge Mella still needs to rule on the recommendations of the public administrator and Kordes and approve payments to them that come from the estate money.

If no qualifying relatives are found, then Gigi’s $25 million would be transferred to the city’s Finance Commissioner, who would hold the money in an unclaimed fund account.

If no qualifying relative comes forward after three years, then the money is transferred to the state comptroller’s office, where it sits in an unclaimed fund or until someone successfully makes a case for it.

While Kordes agreed with the public administrator that state law bars Leonard Carrier and his family from the money, she said his argument resonates because it illustrates the sad social reality that Gigi and Cowell faced.

“I respectfully submit that Leonard’s argument fails on a strict reading of the law, but impacts emotionally and socially where, at the time of the adoption, same-sex couples simply could not marry,” she wrote.