Youth suffrage

Youth suffrage, or children's suffrage, is the right of youth to vote and forms part of the broader youth rights movement. Until recently Iran had a voting age of 15; Argentina, Austria, Brazil, Cuba, Ecuador and Nicaragua have a voting age of 16; and Greece, Indonesia, East Timor, Sudan, and Seychelles have a voting age of 17.
United States.
In the United States, suffrage originally could not be denied on account of age only to those 21 years of age or older; this age is mentioned in the Fourteenth Amendment to the United States Constitution. The Twenty-sixth Amendment to the United States Constitution, ratified on July 1, 1971, lowered that age to 18. The primary impetus for this change was the fact that young men were being drafted to fight in the Vietnam War before they were old enough to vote. There have been many proposals to lower the voting age even further. In 2004, California State Senator John Vasconcellos (D-Santa Clara) proposed a youth suffrage constitutional amendment called Training Wheels for Citizenship that would give 14-year-olds a quarter vote, 16-year-olds a half vote, and 17-year-olds a full vote.
In 2013, Takoma Park, Maryland became the first U.S. city to allow 16- and 17-year-olds the right to vote. On January 5, 2015, Hyattsville, Maryland joined Takoma Park in lowering the voting age to 16.
Venezuela.
A proposal to lower the voting age from 18 to 16 was defeated in the 2007 Venezuelan constitutional referendum.
Impact.
Studies have found no differences in the quality of young voters' voting choices relative to older voters.
A study of preregistration (registering individuals before they are eligible to vote) found that it was linked to higher youth turnout, and that politicians became more responsive to issues that the young have strong preferences on, such as higher education spending. One study found that allowing 16-year-olds to vote led those voters to have "substantially higher levels of engagement with representative democracy (through voting) as well as other forms of political participation".
Demeny voting.
Demeny voting is the idea that parents would cast votes on behalf of their children thereby ensuring that the interests of children were properly accounted for in the voting system. Most young people do not support themselves financially and are reliant upon parents for support, thus parental voting power should be proportionate to the number of dependents, especially where government benefits are concerned, to appropriately counterbalance the interests of the childless. Essentially, a case for "no taxation without representation." However, as children and their parents often have differing political, social, and economic interests, it is doubtful demeny voting would result in any significant advances of youth interests in government.