My parents do that, But I am 19 years old. They let me drink when I was 17 because they want me to learn the dangers and effects, I never asked to let a friend drink too.

But for my 19th birthday they let my bf and I drink, he was 19 too, being that we're both adults and can join the army and die in a pointless war, I've used that logic to get my parents to let me drink at home. Besides he's an adult and knows better not to drive and we made sure he didn't by taking his keys :3.

I think it's okay that they let you do that but I wouldn't let my kids friends drink too. Unless they were 18 years old and I took their keys.