Same-sex married couples will soon be covered by insurers offering benefits to heterosexual spouses on the federal health insurance exchanges under the Affordable Care Act.

The White House announced on Friday clarified rules on coverage for same-sex marriages to be implemented next year. The new rules apply to plans sold on the federal exchange as well as some individual and group plans sold elsewhere. Although only 17 states have legalized gay marriage, millions of same-sex partners gain more equal treatment in the distribution of health coverage across the United States. 

"In other words, insurance companies will not be permitted to discriminate against married same-sex couples when offering coverage," Matthew Heinz, the Department of Health and Human Services's director of LGBT outreach, wrote in a blog post.

The department said the new regulation would make health coverage “more accessible and equitable for married same-sex couples.” Now, insurers providing plans with benefits for heterosexual married partners must offer the same to gays and lesbians married legally in any state permitting same-sex marriage.

Like the state-by-state campaign to liberalize marijuana laws, the movement to permit same-sex marriages in America continues to accelerate. In a 5-4 Supreme Court decision last year, Justice Anthony Kennedy declared DOMA — the Clinton-Gingrich-era Defense of Marriage Act — in violation of the Constitution’s Eighth Amendment prohibiting unequal treatment before law. This week, the Obama administration urged insurers to begin coverage of same-sex married partners ahead of the Jan. 1 deadline.

The White House updated the health regulation after Alfred Cowgers Jr. and Anthony Wesley Jr., a gay couple of Gates Mill, Ohio, complained they could not get family health coverage after marrying in New York, which legalized same-sex marriage in 2011. Among others facing the same battle, the couple last month sued their insurer and the state of Ohio, as the federal government had deferred to state law on the issue.

Many more same-sex married partners may qualify for family health coverage in the coming months following Virginia’s overturned gay marriage ban, and court fights soon expected in Ohio, California, and Colorado, analysts say.