How to filter a view to show current month
in the view select filter type your dob field select apply then another popup opens in which you have to select "Date selection form element" as popup (Provided you have enabled the Date Popup module in Date API package) then "Filter granularity" by month select apply operator should be equal to and in front of that theirs a option select a date .. you have to select enter a relative date and in relative date type now.apply and save