New York will become the latest state to have insurance companies cover gender reassignment surgery, after Gov. Andrew M. Cuomo recently issued a warning that the practice of denying gender reassignment surgery or other treatments to change a person’s gender would no longer be allowed.

The number of U.S. companies covering the cost of gender reassignment surgery for transgender workers has more than doubled in the past year, the NY Daily News reported. Now, thanks to a recent move by Gov. Cuomo, New York will soon be the ninth state in the union to require this coverage, according to the Transgender Legal Defense and Education Fund.

In a letter, which is being sent to insurance companies later this week, the governor explicitly outlines that it is now a state law for insurers to offer coverage for the diagnosis and treatment of all psychological disorders, if a doctor deems them medically necessary. This includes people who have body dysmorphic disorder and believe that their gender identity does not match the one given at birth.

"An issuer of a policy may not deny medically necessary treatment otherwise covered by a health insurance solely on the basis that the treatment is for gender dysphoria,” the governor’s letter read.

Other states with similar rulings include: California, Colorado, Connecticut, Illinois, Massachusetts, Oregon, Vermont, and also Washington, D.C.

Michael Silverman, executive director for the Transgender Legal Defense and Education Fund, told The New York Times that he believes Cuomo’s legislature will be a game changer for transgender health needs.

“This essentially opens up an entire world of treatment for transgender people that was closed to them previously,” he said.

Now patients will no longer have to use fundraisers to pay for their surgery, something that New York State Sen. Brad Hoylman said, “Nobody should be in that position in order to embrace such a fundamental aspect of their personhood.” The Manhattan District Democrat hopes the ruling will help to usher in more transgender civil rights for the Empire State.

According to the letter, insurance must cover everything from hormone treatment to gender reassignment surgery. The Surgery Encyclopedia estimates that there are around 100 and 500 gender reassignment procedures conducted in the United States each year, but Medical Daily reported that in University of Michigan Professor Lynn Conway's most recent report, between 800 and 1,000 are actually conducted.

The surgery requires the complete realignment of the sexual organs, a feat which is more easily accomplished from male to female. The surgery requires both months of preparation and months of recovery.