Its is abuse, they are too young to make the right choices.
100 years ago we had middle age men marring 16 year old girls, we do not want to repeat that.
Look at the ages of the first few Miss Americas
1921, just 16 years old, ugh
http://www.missamerica.org/our-miss-americas/1920/1921.aspx
22-23 a 17 year old won twice, well she was 18 the second time