I'm not against it personally, but here are some arguements-
-If you lower the drinking age to 18 then 18 year old high school students begin purchasing it for their younger high school friends and students under age 18 have a greater ease of purchasing.
-Your brain hasn't fully developed till wayyy past age 18. (Does it ever fully develop? I'm not sure. But its rapidly changing between 18-21)
-At age 18, boys and girls alike are not mature enough to deal with the consequences of alcohol and drinking excessively.
-Basically, by pushing the drinking age to 18 you begin pushing the age of underage drinkers lower and lower.