Exodus 21:31

או בן ינח WHETHER HE HAVE THRUST A SON — a son who is a minor; או בת יגח OR HAVE THRUST A DAUGHTER, who is a minor. Since it states, (v. 29) “and hath put to death a man or a woman”, one might think that the owner is liable only for the death of adult persons, Scripture therefore states, “whether he have thrust a son etc.” to make him liable for the death of minors equally as for that of adults (Mekhilta).

אוֹ־בֵ֥ן יִגָּ֖ח אוֹ־בַ֣ת יִגָּ֑ח כַּמִּשְׁפָּ֥ט הַזֶּ֖ה יֵעָ֥שֶׂה לּֽוֹ׃

Whether he has gored a son, or gored a daughter, according to this judgment shall it be done to him.