In 1906 , The San Francisco earthquake caused a huge fire that destroyed public birth documents . Suddenly a new opportunity for citizenship arose : Chinese men who were already in the United States could claim that they were born in the United States . Other Chinese men would travel back to China as United States citizens and report that their wives had given birth to a son . Consequently , this made the child eligible to be a United States citizen , for which they would receive a document . These documents could then be used for their actual sons , or sold to friends , neighbors , and strangers . This was termed as a " slot " and would then be available for purchase to men who had no blood relationships in the United States in order to be eligible to enter the United States . Merchant brokers often acted as middlemen to handle the sale of slots
San Francisco earthquake
1906 San Francisco earthquake
Paper sons