Dear Vivek ji,
Thank you for your reply..Can you be bit more elaborate about what you said.
But before you tell me to,let me write my understanding
Because parents r the result of anyone's birth thus they r to be considered from D-12 i.ie just before creation of lagna(i.e.before trueself of a native)
In easier words they become reason for creation of a native(lagna)after distruction of body(12th house)of native in previous birth.
I did to reply yesterday but i think something is seriously wrong with Database of mysticboard
Regards,
Raman