China adopts the policy of "one country, two systems" towards Hong Kong, so Hong Kong has its own Marriage Law. In the Marriage Law of Hong Kong, there is no explicit prohibition on cousins getting married, but cousins belong to collateral blood relationships within three generations, and married offspring are prone to health problems. Therefore, it is not recommended for cousins to get married.
Regulations on consanguineous marriage in various countries
Deep blue represents that consanguineous marriage is legal, red represents that laws prohibit consanguineous marriage, light blue represents that consanguineous marriage is allowed to be legal with restrictions, orange represents that legality depends on religious doctrines, pink represents strict prohibition but exceptions, brown represents that consanguineous marriage is a criminal offense, and gray represents that there is currently no data available.
Most countries in Europe, Australia, and the Americas allow consanguineous marriage.