Final answer:
The validity of a contract signed by a 15-year-old depends on the laws regarding the legal capacity of minors in the jurisdiction where the contract was signed. It is best to consult with a legal professional for advice in specific cases like this.
Step-by-step explanation:
The validity of a contract signed by a 15-year-old depends on the legal capacity of minors to enter into contracts. In many jurisdictions, minors are not considered competent to enter into contracts, and any contract they sign may be voidable. However, there are exceptions to this general rule. For example, contracts for necessities like food, shelter, and education are generally valid even if signed by a minor. Whether a health club membership contract falls under one of these exceptions would depend on the specific laws of the jurisdiction in which the contract was signed.
In some cases, if a minor misrepresents their age and appears older, it may be more difficult to argue that the contract is voidable. The health club may argue that they had reasonable grounds to believe the minor was of legal age. However, it would ultimately be up to a court to decide the validity of the contract.
It is important to consult with a legal professional familiar with contract and minor laws in your jurisdiction for accurate advice on the specific circumstances of your son's contract.