Hiat-iân (血緣) sī khū-iú kiōng-tông chó͘-sian ûi te̍k-teng ê chhin-sio̍k koan-hē. Chi̍t ê lâng kap lēng-goā chi̍t ê lâng seng-io̍k ê só͘-ū āu-tāi, í-ki̍p chia-ê āu-tāi chi-kan, lóng sī hiat-iân koan-hē. Hiat-iân sī chi̍t ê seng-bu̍t-ha̍k ê kài-liām, tān-sī tī hoat-ha̍k, siā-hōe-ha̍k téng jîn-bûn ha̍k-kho lāi-bīn iā toā-liōng chhut-hiān. Tī seng-bu̍t-ha̍k ê lí-lūn tiong, in-ūi lâng-lâng lóng ē-tàng tui-sò͘ kàu kiōng-tông ê chó͘-sian, in-chhù lâng-lâng lóng ū hiat-iân koan-hē. Tī hiān-si̍t tiong, nā-sī tī só͘-ū ē-tàng tit-tio̍h ê chu-sìntiong, nn̄g ê lâng chhōe bô kiōng-tông ê chó͘-sian, in tiō bōe khoàⁿ-chò sī ū hiat-iân koan-hē.