Why is the age of adulthood 18 year and not 21? When does the child considered to be “emancipated”?

Full Question:

Why the age of majority is 18 year and not 21 year? What if a child gains economic independence at 17 or 19 year?
04/11/2017   |   Category: Minors   |   State: New York   |   #35477

Answer:

In New York, the minimum voting age in 18 years. Therefore, 18 years serve as the age of majority in most areas of law and not 21 years. Further, parents are statutorily obligated to support his or her child until the age of 21. But, if the child attains economic independence through employment before the age of 21, a parent’s statutory obligation to support his or her child ends.
 
The relevant law is stated below for more details on this subject:

Election Law § 5-102. Qualifications of voters; age and residence
1. No person shall be qualified to register for and vote at any election unless he is a citizen of the United States and is or will be, on the day of such election, eighteen years of age or over, and a resident of this state and of the county, city or village for a minimum of thirty days next preceding such election.
2. The provisions herein with respect to a durational residency requirement for purposes of qualifying to vote shall not prohibit United States citizens otherwise qualified, from voting for president and vice president of the United States.
 
Domestic Relations Law § 2
A “minor” or “infant”, as used in this chapter, is a person under the age of eighteen years.

Family Court Act § 413 - Parents' duty to support child
1. (a) Except as provided in subdivision two of this section, the parents of a child under the age of twenty-one years are chargeable with the support of such child and, if possessed of sufficient means or able to earn such means, shall be required to pay for child support a fair and reasonable sum as the court may determine. The court shall make its award for child support pursuant to the provisions of this subdivision. The court may vary from the amount of the basic child support obligation determined pursuant to paragraph (c) of this subdivision only in accordance with paragraph (f) of this subdivision.
(b) For purposes of this subdivision, the following definitions shall be used:
(1) “Basic child support obligation” shall mean the sum derived by adding the amounts determined by the application of subparagraphs two and three of paragraph (c) of this subdivision except as increased pursuant to subparagraphs four, five, six and seven of such paragraph.
(2) “Child support” shall mean a sum to be paid pursuant to court order or decree by either or both parents or pursuant to a valid agreement between the parties for care, maintenance and education of any unemancipated child under the age of twenty-one years.