The first paper on Tobacco Free Generation : The birth year 2000 is not fixed, but can be any year depending on the community or jurisdiction that adopts the approach. Early adopters chose year 2000 while the later jurisdictions may choose 2005 and 2010 depending on when they start the TFGi mass education.

https://tobaccocontrol.bmj.com/content/tobaccocontrol/19/5/355.full.pdf