BIRTH CERTIFICATE ISSUE

Your grandfather has no business to interfere in your personal affairs.

He might have done it out of anxiety and to help you to obtain the same without any difficulty.

If your relationship with your grandfather is not cordial and if you want to take revenge against your grandfather, then you can proceed. 

Consult and engage a local prudent lawyer with relevant records for proper appreciation of facts, professional avise and necessary proceeding to rectify the certificate and action against your grandfather as desired by you 

first certificate only admitted second is not admitted every where like document case otherwise second is forgery 

You can proceed with the genuine certificate obtained by you following the procedures of law and can record the same everywhere the certificate is required to be produced.

You can ignore the fake certificate obtrained by your grandfather and if necessary you can give a complaint against him for this fraudulent act as well as his malafide intention to ruin your child's career and future  life by such fake documents.

You can approach civil court with a suit for mandatory injunction to direct the authority concerned to cancel the fraudulent entry in the register for births and deaths with reference to your child's  birth registration and also to direct the authority to make a fresh entry with correct details of the birth of your child if the previous correct entry was cancelled or deleted. 

Yes, you can approach the High Court, However, the posting suggests deeper issues, Please post complete facts.

It appears that you are in pursuit of settling some personal issues with the grnadfather than correcting a mistake. In the instant case, you could have ignored wrong registration, But, instad you have sought to cancel the allegedly wrong registration and the issue has boomranged.

Things could turn out to be counterproductive if you appraoach the Court, that too, the Hiigh Court with hands which are less than clean.