The proper precedence[1]
…אשה כי תזריע וילדה זכר וטמאה שבעת ימים וגו’
…when a woman gives birth to a boy, she shall be spiritually impure for seven days…[2]
At the end of the previous parsha[3], there were many details related to the spiritual impurity imparted by animals. This week’s parsha begins a long series of laws related to the spiritual purity and impurity of humans. Seemingly, the order is backwards. Since mankind is the principle player in the Torah, shouldn’t their laws come first? That which is primary takes precedence over what is secondary. Why then are the laws of animals taught first? Rashi addresses this[4], by reminding us that in the Torah’s description of creation, first the animals were created[5], and only then mankind[6]. Just like the animals preceded Man during creation, their laws of impurity are taught first.