Cheng-chú (精子), he̍k-chiá cheng-thâng (精蟲), sī cha-po͘ ia̍h-sī kî-thaⁿ hiông-sèng seng-bu̍t ê seⁿ-si̍t sè-pau. Cheng-chú kap loán-chú kiat-ha̍p liáu-āu ē hêng-sêng siū-cheng-loán, koh chìn-chi̍t-pō͘ hoat-io̍k chò phoe-thai.

Cheng-chú chham loán-chú chiap-chhiok siū-cheng ê sùn-kan.

Tùi āu-tāi (jī-pōe-thé) lâi kóng, cheng-chú sè-pau thê-kiong tāi-iok chi̍t-poàⁿ ê ûi-thoân bu̍t-chit. Tī chhī-leng tōng-bu̍t tiong, āu-tāi ê sèng-pia̍t sī iû cheng-chú koat-tēng: hâm-iú Y jiám-sek-thé ê cheng-chú chāi siū-cheng liáu-āu ē hoat-io̍k chò hiông-sèng ê āu-tāi (XY hêng); hâm-iú X jiám-sek-thé ê cheng-chú chāi siū-cheng liáu-āu ē hoat-io̍k chò chhu-sèng ê āu-tāi (XX hêng); tī siū-cheng ê kòe-têng tiong, loán-chú kan-na ē thê-kiong X jiám-sek-thé. Cheng-chú siōng-chá sī iû Leeuwenhoek tī 1677 nî koan-chhat tio̍h.