How to use array of date?

I’ve a form wherein user can add his child information. He can add or remove child. Child information simply includes child’s dob. Now, in my tempalte, I’m assigning it to a scope variable like this ng-mdel="signup.child" where I’ve initialized this variable in controller as $scope.signup.child = [] and $scope.signup.child = [new Date()] but nothing seems to work. Please help me out