Legal analysis: If there is an agency relationship between parents and children, the act of parents signing a house sales contract on behalf of their children is valid.

Legal basis: According to Article 162 of the "People's Republic of China and Civil Code": Civil legal acts performed by an agent in the name of the principal within the scope of agency authority shall not be liable to the principal. The agent becomes effective. According to Article 165 of the "People's Republic of China and Civil Code": If the authorization for agency is in written form, the power of attorney shall state the name of the agent, the matters of agency, authority and period, and shall be signed by Signed or stamped by the agent.