code: public function getBirthDate($params = [], $format = 'Y-m-d')
  	{
  		$params['min_year'] = array_key_exists('min_year', $params) ? $params['min_year'] : date('Y') - 80;
  		$params['max_year'] = array_key_exists('max_year', $params) ? $params['max_year'] : date('Y') - 20;
  		return $this->getDate($params, $format);
  	}
docs: Generate a reasonable birth date.	 Default Age: 20-80 years.
  
  @param array $params Associative array with following keys: minYear, maxYear, minMonth, maxMonth
  @param string $format date() format for return value.  Default: Y-m-d
  @return string formatted date string.