Polygamy was banned in China in 1930 when the Republic of China government promulgated Civil Code (Part IV) where Section 985 states "A person who has a spouse may not contract another marriage. A person shall not marry with two or more persons simultaneously." This is still in effect today in the territories under effective administration of the Republic of China including Taiwan and Kinmen and Matsu. However, as infringement of marriage cannot be prosecuted without a complaint by the wife, one can still unofficially practice polygamy by registering only one marriage. Such practice still happen occasionally among older and wealthy men. After the establishment of the People's Republic of China by the Chinese Communists on the mainland, this banning was reaffirmed in the passage of the Marriage Code of 1950. In Hong Kong, new polygamous marriages were no longer legally allowed after 1971 with the passage of the Marriage Act. Due to this, incidents of extramarital affairs are rising. Some men have even established a family with their mistresses and children kept secret from their wives. There is a phenomenon of cross-border polygyny usually involving Hong Kong men and their mistresses living in Mainland China.