What's the risk of a teen drinking beer at a young age?!

None.

Other then it is empty calories. As for getting drunk, medically there is no difference once you past puberty. In fact there are many cultures that allow teens to drink. The US is simply the only country with the strange idea that an adult has to be older to drink. The US drinking laws have little to do with logic or medicine and allot to do with politics.

The same risks as an adult would face...i.e., it could lead to kidney/liver failure (BUT ONLY IF YOU DRANK LOTS [over 3 units a night] OVER A LONG PERIOD OF TIME [10 - 20 years maybe?])

But if a person isn't used to alcohol (a 15 year old probably wouldn't be that used to it, if at all) drinking lots in a short period of time could make them sick.

But a 15 year old drinking a "light" beer would have very low risks.

15 isn't that young and how drunk you get off of any beer depends on who you are. If you're 15 and you drank a light beer you're fine. If you drank 10 then that's dangerous but 1 to 3 is alright. Even though people would say you don't need to be drinking anyway, who cares. We all do what we want. Lol.

behavior problems and may probably risk themselves for cancer later in life...i have many classmates who started drinking at 13. They don't have behavioral problems but i think the effect is more on the health...

kids do NOT drink lite beer they drink in excess to get drunk.... they then cause mayhem and are a public nuisance. being abusive to people, hanging around parks etc.

There is a risk that you might end up inside a fat body.

jail
probation
liver damage
brain cells damaged
kidney damage

he can lost his immunity power.