this javascript code is not working. when i debug it says $('.gender option:selected').val() is undefined. Please help

$(document).ready(function () {
  $('.cf-collection-block').on('blur', 'input', showresult);
  
  function showresult() {  
    if($('.gender option:selected').val() == 'Male')
       {
         $('.name input').val("Male");
       }
    else
    {
      $('.name input').val("Female");
    }
  }
  
});