It's now legal for couples in all U.S. states to adopt children — regardless of the couple's gender — after a federal judge struck down Mississippi's ban on same-sex adoption late Thursday.

Overturning a law that had stood since 2000, U.S. District Court Judge Daniel P. Jordan III said the ban violated the U.S. Constitution's equal protection clause. Mississippi's ban was the last of its kind in the U.S.

"I'm a happy camper. Our clients are beyond happy campers. They are more than thrilled," the plaintiffs' lead attorney, Roberta Kaplan, tells Mississippi Today.

The lawsuit challenging the law was filed back in 2015 by four same-sex couples; it's also backed by two advocacy groups, the Campaign for Southern Equality and the Family Equality Council.

The couples in the case were in a variety of circumstances, from desiring to adopt a child to raising children together. Here's how the Jackson Clarion-Ledger described them last year:

"Kari Lunsford and Tinora Sweeten-Lunsford, who are seeking to adopt a child; Brittany Rowell and Jessica Harbuck, also seeking to adopt; Donna Phillips and Janet Smith, parents to a young daughter; and Kathryn Garner and Susan Hrostowski, who have a 15-year-old son."

Copyright 2016 NPR. To see more, visit http://www.npr.org/.