Why do school children carry their books (especially inside) differently based on their gender?
Girls of course, tend to carry their books with both hands …books next to their chest…boys tend to carry them in one hand, books pressed against their side.
is it an issue of upper body strength?
Is it sociologically learned …more “lady like” to carry them in front…and thus passed down as learned behavior over generations?
Oh baby. 
As soon as I saw this thread title, a synapse clicked and I said automatically, “Girls carry their books cradled in their arms, boys carry books in a stack balanced casually on the hip.”
Yep, you’re absolutely right, and my big 99.9% certainty WAG as to why this is so would be “sociological”. Speaking as a girl growing up during the 1960s, I knew without having to be told that “girls carry their books this way, and boys carry their books THAT way.”
And girls only carry their books against their chest until one of two things happens. (A) Eventually their breasts get too developed to do it comfortably, and carrying books that way tends to draw unwanted attention to them, or so says the newly self-conscious budding female. OTOH, sometimes the budding female WANTS to draw attention to that portion of her anatomy, so why cover it up with books?
And (B) the books themselves get too heavy. A stack of books that includes textbooks for chemistry, algebra, and American history (somebody shoot me, how the memories come flooding back… :rolleyes: ) will give you a backache if you try to clutch it to your chest all the way home.
Au contraire, my triple fowl and canine friends. Tho there is a gender difference, it is that girls carry their books balanced on their hip, while boys carry them with their arm haging straight down. It is only if the boy has an excessive load to carry, that he would carry them “like a girl.” That’s the way it was where I went to school in Chicago in the 60s, and that’s the way it is today in the western suburbs judging from a conversation I had with my 13 year old daughter over the weekend (which caused me to be quite amused upon seeing this thread title.)
Here’s my WAG. Carrying them on the hip makes far more sense, which is why girls, maturing more rapidly, assume this method. Boys, essentially being ignorant men in the making, revolt against doing anything “like a girl”, whether it be holding their books a certain way, or asking directions while driving. So they willingly adopt a less sensible alternative, simply to be different.
I guess I should point out that carrying the books in front of the chest is a secondary option available to girls only.
Sheesh! Do I have to explain EVERYTHING to youse guys?
I have always thought it was because boys tend to be stronger and do not need the extra help balancing them on the hip provides unless the books are extra heavy. Holding the books in one hand means you can walk faster and more naturally than if you have to balance on the hip.
Where are there still school children carrying books either of these ways? 'Round here, they’ve all got backpacks.
mostly elementary and grade school kids…
some schools are also opposed to backpacks due to security issues…
I always thought girls carried 'em on their hips because girls HAVE hips. When I carry a book, I sort of rest it on my hip bone. Seems to me that boys don’t have the ‘hourglass’ figure that results in there being a slight shelf on the hip to jam a book into, and that’s why they don’t carry their books that way.
Holy shit, did I laugh at the O.P. A good laugh, I’d not thought of this kind of thing in decades. Yes, I’m old.
In elementary school, kids keep their workbooks in their classroom. Carrying books was rare.
In Jr. High, now known as middle school, two HUGE things happened. You had to carry materials from class to class, and you hit puberty.
I got an erection on Tuesday, October 11th, 1975. I lost that erection somewhere in the morning of Friday, April 23rd, 1977. I kept my textbooks clamped against my hip bones, and crossing my pelvic extremeties for reasons that have NOTHING whatsoever to do with hi[ structure or balance points.
I’d always believed that the young ladies populating both the daytime hallways and nighttime fantasies of my Jr. High School years suffered the same self-consciousness, and held their school books and binders to their bosoms for the same reason.
And, I prefer to believe that still. 
Cartooniverse
The explanation I have heard is that it goes back to prehistoric habits. Females carry their books the way they would cradle a baby (across their chest), while males carry their books the way they would carry a spear (to their side).
It’s cultural, folks. I still remember the day in junior high when one of my friends informed me that I was carrying my books like a girl, after which I made damn sure to carry my books in proper boy fashion from that day forward.
I noticed the difference in how guys and girls carried books when I was in elementary school. When I got to junior high, I carried my books with both hands or on my hip just because they were too heavy and cumbersome to carry any other way, not necessarily because it was the “proper” girlish way.
Just my two cents.
I’ve gotta second Cartooniverse here…
I still carry my books strategically positioned in front of my crotch since I was 12. 23 years and counting!
Off to the thread on priapism…
" Females carry their books
the way they would cradle a baby (across their chest), while males carry their books the way
they would carry a spear (to their side)."
I read that too. But these days everyone has a backpack.
If you have kids, they should not have to carry more than 10% of their body weight in books, etc. Locally, in our middle school I found the backpack weighed in at 18lbs about 20% of the body weight.