Learn about rules governing a contract with a minor. A minor may disaffirm a contract at any time during minority or upon reaching majority.A minor may rightfully disaffirm any contract into which they enter, whether or not it has already been performed. Understanding Disaffirmance. Under New York State law, generally you must be at least eighteen (18) years of age to enter into a contract, unless a parent or legal guardian signs as well. The prosecuting attorney of the county in which the minor's parents are living must approve the contract in writing before it is signed. When voiding contracts, minors must return any received items in reasonable condition. This reflects basic fairness principles in contract law. A minor can not enter into a contract in New York. New York law says that children are entitled to share in the income and standard of living of both parents.