A senior US District Judge has temporarily blocked a new rule put forward by US President Joe Biden's administration to safeguard healthcare rights for transgender individuals under the Affordable Care Act.

Judge Louis Guirola of Gulfport, Mississippi, issued a preliminary injunction against the rule, which was due to take effect on 5 July and extend the prohibition of sex discrimination to include gender identity.

The Department of Health and Human Services (HHS) finalised the rule in May, interpreting the Affordable Care Act's prohibition on sex discrimination as being applicable to transgender individuals.

This move was in line with Biden’s executive orders from 2021 and 2022, directing agencies to prevent discrimination against transgender people.

Challenging the rule, 15 Republican-led states filed a lawsuit, arguing it would force their Medicaid programmes to fund gender-affirming treatments, including for minors.

Guirola said these states were likely to succeed in their legal challenge, suggesting that the administration exceeded its authority by expanding the definition of 'sex' to encompass gender identity.

The HHS argued that these concerns were unfounded and that the rule did not interfere with medical professionals' judgment, but Judge Guirola highlighted the immediate financial burden of compliance as a reason for his decision.

Subsequent rulings in Florida and Texas by other judges prevented the enforcement of the rule in those states, along with Montana.

Among those who opposed Judge Guirola's ruling were Human Rights Campaign, an advocacy group that supports transgender rights.

Human Rights Campaign president Kelley Robinson said: "This ruling is not only morally wrong, it's also bad policy.

"Everyone deserves access to the medical care they need to be healthy and thrive."

The rulings followed a Supreme Court decision that limited the power of federal agencies to interpret ambiguous laws.

Judge Guirola acknowledged this but deemed the law clear in its intent.