en_tn/gen/04/18.md

To Enoch was born Irad

This can be translated as "Enoch had a son and named him Irad" or "Enoch became the father of Irad." Verse 17 told about Enoch being born. Verse 18 tells about Enoch having a son. The implied information is that Enoch grew up and married a woman. This can be made explicit as it is in the UDB. (See: rc://en/ta/man/translate/figs-explicit)

Irad became the father of Mehujael

This can be translated as "Irad had a son and named him Mehujael."