The measure's sponsor, the Arkansas Family Council, had tried to paint its proposal as a battle against a "gay agenda." The conservative group successfully pushed for an amendment banning same-sex marriage four years ago.
Opponents of the measure argued it would make it harder for the state to find the foster parents it needs to take care of children.
To watch comments from Family Council Action Committee President Jerry Cox, click here.
For a complete list of election results, click here.