Minimum Drinking Age

Under the 1984 National Minimum Drinking Age Act [23 U.S.C 158], persons under 21 years of age are prohibited from purchasing alcohol in all 50 US states. although there are exceptions in certain states when alcohol is consumed at home, under adult supervision, and for medical purposes, the drinking age still stands.
There are moves to lower the drinking age, however. many proponents think 18 is a good number, considering that teenagers at this age are practically considered adults. in fact, they think it is hilarious that an 18 year old can marry, vote, join the military or buy guns, but can 't buy or drink alcohol, which is probably the easiest thing anyone can do, as opposed to getting married and choosing the next president. Well, they should be happy now the rule has been amended, since the law to lower legal drinking age to 18, which was signed by President Obama, has taken effect last June 4, 2015.
But

When it was time to compare the drunk driving traffic accidents and fatalities, countries with a lower drinking age also has lower traffic accidents than the U.S.
There was a period, however, when such fatalities decreased. But because it happened before an MLDA was established by the Uniform Drinking Age Act, the decrease cannot be attributed to the drinking age of 21.
Reduce the thrill of violating the law
Remember the ‘forbidden fruit syndrome’? If people aged 18 years old are allowed to consume alcohol legally, they would not consider breaking the law just to get their way, or even try to prove a point. This may cause a problem with younger people aged below 18, but that is another story.
This can also lower the high rate of non-compliance with MLDA 21, where teenagers tend to get creative, procuring fake IDs and deliberately disrespecting the law.
List of Cons of Lowering the Drinking Age
Health