graeme_p - 8:17 am on Jun 18, 2011 (gmt 0)
One thing to bear in mind is that the countries that are strictest about giving children alcohol (legally and culturally) seem to have the biggest alcohol problems - especially if you look around Europe. Take a look at this EU report:
especially the map on page 31 of the PDF (105 as printed).
There is a nice world map on page 21/95. I live in one of the countries marked in red and it is very anti-alcohol culturally and legally.
I would say start with diluted wine in small quantities (which can start fairly young) or the occasional sip from your glass and gradually increase over the years.