The Trump administration began its implementation of a policy banning most transgender individuals from enlisting to serve in the military Friday two years after the president proposed the change.

Individuals who continue to identify as their biological sex can still serve under the rule that could affect an estimated 15,000 service members, according to CBS News. There will also be waivers for certain individuals already serving, ABC News reported.

Surgery for gender transition will no longer be permitted, unless the process has already begun.

Military personnel will handle future diagnoses of gender dysphoria on a case-by-case basis, said Anthony Kurta, acting deputy undersecretary of defense for personnel and readiness.

“If the service member can continue to meet all standards, including deployablity standards, and all those associated with their biological sex, then the service member can continue to serve without waiver,” he said, according to a Defense Department press release.

LGBTQ advocacy groups denounced the changes. ABC’s “The View” hosted two transgender service members opposed to the policy on Thursday’s show.

WATCH:

The military defines gender dysphoria as “a marked incongruence between one’s experienced/expressed gender and assigned gender … associated with clinically significant distress and impairment of functioning,” according to the Defense Department guidelines.

The ban comes two years after President Donald Trump tweeted about making a policy change.

“After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow transgender individuals to serve in any capacity in the U.S. Military,” he wrote.

Since that announcement, several lawsuits have been filed to enjoin the proposed ban. A federal judge lifted the final injunction to the ban in March, allowing the Pentagon to move forward with the policy.