Where to find out my grandfather's true age, by what method?

http://www.familysearch.org/ has millions of listings, including those for Mexico. Go to the page to SEARCH RECORDS, type in his name, and under " Event --Year-- Year Range" , click "Birth & Christening" for Event; going from 2009, 96 years ago was 1913 and 106 years was 1903.

I used the following as an example:

Manuel Garcia

Birth/Christening, *1898 - 1918, Mexico

Exact Spelling: Off ( this can be clicked to use his name's exact spelling, but no other field but his name can be entered)

Matches: All Sources - 30

(*--which would cover the 1903-1913 years)

The 30 matches this lists is in :

Ancestral File - 2

• IGI/Mexico - over 25 (could mean 26 or 2000+)

Pedigree Resource File - 3

The site is free to use, but if you are still having trouble, my email is in my profile and I'll see what I can do to help. =)

Boy thats a hard one. The only way to find his age if there is no record would be by medical means. That is , that a doctor could give you an age within a couple of years by the deterioration of some tissues in the body. But this can be an expensive proceedure, so if you don't plan on spending some dough , you'll never be in the know....

Boomer Wisdom gave a good answer - church records. Try to get a copy of his baptismal record in Mexico. Usually a baby was baptized not too long after they were born. Now, if he was in a rural area he might have been about a year old.

Two words:

Church records.

More words: search primary records, not what's on the net.