This chapter would more naturally follow the 15th chapter of Leviticus. See the note to Leviticus 15:1.

And when the days ... — Having described in the previous verses the conditions of defilement arising from childbirth, the…

And when the days of her purifying are fulfilled, for a
son, or for a daughter
For a …

After the laws concerning clean and unclean food, come the laws concerning clean and unclean persons. Man imparts his depraved nature to his offspr…