I think, the certificates issued by Indian Embassy are not acceptable to verify your DOB/Marriage. I can site the following reason for this:
1)DOB at the Embassy is issued based upon your Passport
2)DOB on passport is issued based on your 10th Std. School Certificate/Ration Card
3)DOB on School Certficate is issued based on well "nothing", just parental knowledge etc.
Therefore, INS requires DOB be issued by the hospital/doctor from the place you were born.
Else, other documents like affidavit/non-availabilty document etc.