Most people who made it past early childhood could definitely survive to see grandkids as early as 25 or 30 years old. I'd prefer to live into my 80s however an

Most people who made it past early childhood could definitely survive to see grandkids as early as 25 or 30 years old. I'd prefer to live into my 80s however and to do that with a high probability of success requires a little more knowledge than our ancestors had, imo.