An attempted contract that is made for an illegal purpose or that is against public policy cannot be enforced by either party and is void. In contrast, a contract that is made by a minor (usually under age 18), or that is based on a mutual mistake, or that was made on the basis of a fraudulent misrepresentation by one party, is voidable and may be rejected by a party who was at a disadvantage when the contract was made. A voidable contract may also be ratified and accepted by such a party—after a child reaches the age of majority (usually 18), or the parties become aware of their mutual mistake, or a party learns of the other party’s misrepresentation and proceeds with performance of the contract.

In Louisiana, contracts made for illegal purposes or against public policy are void and unenforceable. This aligns with general contract law principles that prohibit the enforcement of agreements that involve illegal acts or that significantly contravene societal standards. On the other hand, contracts involving minors, mutual mistakes, or fraudulent misrepresentations are categorized as voidable. This means that the disadvantaged party, such as a minor, a party to a mutual mistake, or a victim of fraud, has the discretion to either reject or ratify the contract. In Louisiana, the age of majority is 18, at which point a person gains full legal capacity to enter into contracts. If a minor chooses to ratify a contract upon reaching the age of majority, the contract becomes fully enforceable. Similarly, parties to a contract can choose to proceed with the contract after discovering a mutual mistake or fraudulent misrepresentation, thereby ratifying the agreement. It's important to note that Louisiana's civil law system is unique in the United States and has specific statutes and codes that govern these matters, which may differ from common law principles in other states.