An Alabama lesbian couple on Wednesday filed a federal lawsuit challenging a part of the state's ban on gay marriage.

Cari Searcy and Kimberly McKeand have been together for over 15 years. They exchanged vows in California in September of 2008.

In 2005, McKeand gave birth to the couple's son, K.S. In 2012, a state judge denied Searcy's request to adopt K.S. Judge Don Davis determined that Searcy is not a “spouse” of McKeand. Alabama law provides that couples must be married in order to adopt their partner's children.

The women are asking the court to recognize their California marriage so that Searcy may adopt K.S.

“There is no articulable reason why Searcy is not allowed to adopt K.S. other than the fact that she is a woman married to another woman,” the lawsuit states.

In a press release announcing the lawsuit, Searcy said: “I am a parent in every way to our son, but legally I am still considered a stranger. We just want our son to have the same protections and securities as other Alabama families.”

“Because the legislature and the state government refuses to recognize the marriage of same sex couples; the little boy born to this married couple, has been denied the right and protection to have two legally recognized parents,” said Christine Hernandez, an attorney representing the couple. “A law that is based on irrational prejudice with no legitimate purpose is unconstitutional.”

The lawsuit is the second to challenge Alabama's 2005 voter-approved constitutional amendment which outlaws same-sex marriages from being performed or recognized in the state.