Parents Marriage Certificate

[raj365 0]

I'm interested in applying for GC for my parents (India). They don't have a marriage certificate, also no one is alive to be a witness for an affidavit. I'm also not sure if there's any record since marriage date goes back to 1964. I would appreciate any ideas/guidance here. I have heard mixed reviews about getting it through Indian consulate in US - https://www.cgisf.gov.in/page/marriage-certificate/, does USCIS accept it? What are my other options? 

Thank you for the help. 

[pontevecchio 12]

U.S. Visa: Reciprocity and Civil Documents by Country (state.gov)

No alternates have been mentioned for a Marriage before 2006.

E. For parent-child relationships only: If other forms of evidence have proven inconclusive, the petitioner may submit on a voluntary basis other evidence of a birth parent and birth child relationship to include deoxyribonucleic acid (DNA) testing. DNA test results will only be accepted by USCIS from parentage-testing laboratories accredited by the American Association of Blood Banks (AABB). A list of laboratories can be viewed at www.aabb.org/sa/facilities/Pages/RTestAccrFac.aspx.

[raj365 0]

Thank you for the info. According to this - https://travel.state.gov/content/travel/en/us-visas/immigrate/family-immigration/dna-relationship-testing-procedures.html, it's unclear if this process is used if you go through the conseler processing. Do you see if this can work if I applied for the green card if I applied for it when they in US?

Thanks!