What are adults attitudes toward teenage drinking?

ALCOHOL. As much as possible, adults don't permit early exposure of teenagers to alcohol.But they follow the peer group and do it anyway. It also depends on their friends and their influence.
Variable. In Spain & the Netherlands - the legal age to drink is 16 years old. In Western Europe the majority of teens begin alcohol use by age 15 to 16 years old. In many countries wine is standard at the dinner table (for people of many ages). So - I would say that different adults have different attitudes. I personally do not recommend that any teenagers drink alcohol because it can be a slippery slope.