Jerez, Zacatca 1836 Baptism records

Hello Everyone,
I am researching my family currently from the Jerez Baptism records for 1836. I have noticed a large amount of record with no grandparents listed. Instead, it says "abuelos no dio rason". I've only seen this so far in the Jerez records but don't know what it means since it's on so many records.

Hope someone can tell me what that means??

Thanks,