Unless the identity of the father is unknown, or the father renounces paternal rights and allows his children to be adopted by the mother, the children of foreign fathers cannot be included in the family's household registration.
除非是「父不詳」，或父親放棄親權由母親領養自己的孩子，否則洋女婿的孩子在台灣沒有戶籍，有如「幽靈人口」。