jQuery Validate, out of two blank fields, at least one field must be filled or both

I want to validate my form so that is out of two blank fields, at least one field must be filled and two fields also can be filled; but can't leave any field blank.

I'm using jquery-1.9.1-min.js and here is my html page.

<form action="#" class="send_form" id="forgot_pass_form" method="POST">
            <fieldset>
                <div class="send_row">
                    <label class="padding-top10">Email</label>
                    <input type="text" class="send_email" id="email" name="email" />
                    <em>You need to type an email address</em>
                </div>

                <div class="send_row option">OR</div>

                <div class="send_row">
                    <label class="padding-top10">Username</label>
                    <input type="text" class="send_username" id="uname" name="uname" />
                </div>


                <div class="send_row send_submitforgotuser">
                    <input type="submit" value="Submit" />
                </div>
            </fieldset>
            </form>

Any suggestion how to do it.... ?

sofar I have tried

 jQuery.validator.addMethod("require_from_group", function(value, element, options) {
    alert("xxx");
    var valid = $(options[1], element.form).filter(function() {
        return $(this).val();
    }).length >= options[0];

    if(!$(element).data('reval')) {
        var fields = $(options[1], element.form);
        fields.data('reval', true).valid();
        fields.data('reval', false);
    }
    return valid;
}, jQuery.format("'Please enter either username/ email address to recover password'/Please fill out at least {0} of these fields."));

Still not getting friutful output.