The following content is not legal advice and is for reference only. You should consult a professional lawyer based on the specific laws of your location to obtain advice tailored to your specific situation. When it comes to minors, the laws of various countries (or regions) usually have clear provisions: Even if the parties have subjectively misunderstood the identity or age of the other party, sexual behavior involving minors may still constitute a crime (for example, statutory rape or sexual assault on minors), and some laws adopt the principle of strict liability and do not allow exemption from liability due to false statements by the other party. Generally speaking, if an adult discovers that the other party is actually a minor after the fact, and proves that the other party has deliberately made false statements or concealed his true age, the adult party may try to take the following measures to seek legal protection for himself, but it should be noted that the specific circumstances and applicable laws may vary from region to region: 1. Collect and preserve relevant evidence: • Keep the chat records, call records, text messages, social platform conversations, etc. of both parties, which can prove that the other party has claimed to be an adult in some way; • If there are written, pictures, videos or other materials that can prove the identity information of the other party, they should also be properly preserved. These evidences may play an important role in seeking help from lawyers and proving the "deception" later. 2. Actively report and consult professional lawyers in a timely manner: • Once you find that the situation is abnormal, it is recommended to stop all further sexual behavior immediately; • Contact a qualified lawyer as soon as possible, explain the whole process to him, and ask the lawyer to help determine whether the other party is defrauding and how to hedge against possible criminal charges; • Actively report to the relevant law enforcement agencies that you were misled by the other party without knowing it, and strive for the police and prosecutors to pay attention to the other party's fraudulent behavior during the investigation. Of course, this step must be carried out under the guidance of a lawyer to avoid adverse effects caused by misrepresentation. 3. Emphasize your own fault prevention measures: • Prove that you have a reasonable duty of care when the sexual behavior occurs (for example, the other party deliberately conceals or makes false statements), but you should also recognize that most legal systems require adults to verify the identity and age of the other party before engaging in sexual behavior. This fault investigation may be considered in the trial; • If conditions permit, prove that you have fulfilled your reasonable care and prevention responsibilities, such as having a record of identity verification and taking inquiries or other measures when there is reasonable suspicion, but because the other party disguises, the real age cannot be discovered. 4. Cooperate with the investigation and provide the truth: • During the investigation by the judicial authorities, explain the whole process according to the facts and provide all evidence that can prove that the other party has made false statements or falsified their identity; • Actively cooperate with the investigation of the police or the procuratorate in order to clarify the truth and strive for a more favorable legal position for yourself. Special attention should be paid to the following: • In many jurisdictions, even if the other party makes false statements, adults still have a "legal duty of care". Some local laws stipulate that as long as sexual intercourse occurs, even if the other party is found to be a minor afterwards, legal liability may be pursued. • Therefore, carefully verifying the identity and age of the other party in advance is the best preventive measure; once a problem is found, the behavior should be stopped immediately and legal assistance should be sought. In summary, the key to adults obtaining legal self-protection in similar situations lies in the actions before and after the incident: ensuring the true identity of the other party through reasonable means in advance, and collecting evidence, consulting professional lawyers and cooperating with law enforcement investigations in a timely manner when problems are found afterwards. However, there are differences in legal provisions and judicial practices in different regions. It is recommended to contact professional legal advisors as soon as possible to ensure that their rights and interests are protected to the maximum extent within the legal scope.