I presume the practical part of things refer to lochia. I know the internet says “2 to 4 weeks but as much as 2 months”. For mine, it was always closer to 2 months, but then again, I never took it easy, and I presume the ancient Hebrew ladies didn’t, either…
I do remember catching a snippet from Fr Mitch Pacwa where he was talking about ritual impurity. He had brought up the point that when people come in contact with the Divine— you (become? not quite the word I’m looking for?) sacred as you come in contact with something sacred. I think there might have been something about parallels between the ritual impurity that comes from childbirth, and the ritual impurities that come from touching the Torah barehanded.
So I’m wondering if having a male child vs a female child isn’t so much “a female child is dirty and so it takes longer to purify yourself afterwards”, but more of a “a female child has a very unique potential to cooperate with God’s plan in a very distinct way” and thereby has more potential to come in contact with the sacred in a very distinct way in the future, if that makes sense.
Maybe other moms have experienced this, and not to hijack the thread-- but, for example, for each of my kids, I found myself coming in contact with the divine in a very unique way. For the first, it was being able to experience the Love of God, just a bit of it, just for a few moments. I thought it was just a normal-Mom-thing and I was really looking forward to it for my second.

And then I was so sad when I didn’t feel that same wave of love. Instead, what I got was driving down the road, and looking at the mama cows in the fields, and they had their babies next to them— and just suddenly getting this feeling of the unity of creation, if that makes sense, running ages back into the past, and running ages into the future, and just this whole interconnectedness, and knowing that I was quietly playing my part in this continuity, just like the cows were quietly playing their part… It was really weird, but it was profound, in its own way.
So, yeah. That’s my hypothesis.