Parents Who Host, Lose the Most.

Parents Who Host Lose the Most is an awareness campaign, reminding parents that it is unsafe, unhealthy, and unacceptable to provide alcohol to minors. 

Young people aren't just small adults. Their (amazing) brains are  growing and developing, and will continue to do so until they are 25!  

Even if young people drink while supervised and have their keys taken away, drinking alcohol can cause permanent damage to their developing brains.   

In addition, car accidents are not the ONLY accidents drinking can lead to. Some other physical dangers of underage drinking include accidental injuries from falls, drownings, exposure to violence, sexual assault, and unprotected sex.

Maybe, but believe it or not, studies show teens and young adults  actually do feel that their parents should have a say in whether they  drink alcohol or not. Studies also show that kids who's parents allow  them to drink at home are MORE likely to binge drink outside the home.  Good intentions aside, you're not teaching them to drink responsibly, you're teaching them you are OK with them drinking. 

While this is true, it doesn't mean it's safe. It also doesn't mean that you can't be held responsible if your child is injured, or worse, after drinking alcohol. A parent or guardian may be arrested if they knowingly  provide unreasonable amounts of alcoholic beverages, illicit or  prescription drugs (not prescribed to the child) in a manner likely to  be injurious to the physical, mental or moral welfare of a child less  than 17 years of age. (Source) 

On the same note, many parents allow their own children AND their friends to drink alcohol, which is illegal. You cannot provide alcohol to anyone else's child, period. This is considered  unlawfully dealing with a child in the first degree, and is a Class A misdemeanor. (Source)

More reliable information about underage drinking can be found here.