Form_Dropdown with Blank "Select One..." Option

[eluser]dhall[/eluser]
Here's an example.

Controller:

Code:

$data['gender_options'] = $this->dropdown_model->get_genders();

Model:

Code:

function get_genders()
  {
    $options = array (
      'male' => 'Male',
      'female' => 'Female'
    );
    return $options;
  }

View:

Code:

echo form_label('Gender: ').br(1);
echo form_dropdown('gender',$gender_options,$gender_answer);

So in html this shows:

Code:

<label>Gender: </label>
<br>
<select name="gender">
<option value="male">Male</option>
<option value="female">Female</option>
</select>

I want it to show:

Code:

<label>Gender: </label>
<br>
<select name="gender">
<option selected="selected" value="">Select One...</option>
<option value="male">Male</option>
<option value="female">Female</option>
</select>

And if they do not select one then it returns an error.