The suit aims to overturn a 2010 North Carolina Supreme Court ruling that upheld state adoption laws that exclude unmarried couples, both straight and gay, from jointly adopting children.
The lawsuit says second parent adoption is the only way a North Carolina family with gay or lesbian parents can ensure that both parents have a legal relationship with their child. Civil liberties groups say that children are at risk without such a relationship and can be excluded from benefits like health care.
Terri Beck and Leslie Zanaglio said they were shocked when Beck was denied legal custody of the two young boys they adopted together from the foster care system.
"It sort of took us by surprise," said Beck.
The Morrisville couple is one of the six couples who are suing. They want legal custody rights for both parents of adopted children in any gay or straight relationship.
"We worry that if something were to happen to me, an auto accident, incapacitated [or] God forbid I die, what would happen to these children," said Zanaglio.
The ACLU said the legal protection would keep families together and also ensure either parent could make medical decisions for their children. However, opponents say the suit doesn't defend the best interests of the children.
"We have thousands of studies that show the best environment for raising children is with a married father and mother," said Jere Royall, with the North Carolina Family Policy Council. "Men and women are uniquely created to complement each other as husband and wife, and as father and mother."