The philosopher Friedrich Nietzsche in 1882 took it for granted that upper-class women, at least, were expected to know literally nothing about sex:
I strongly suspect Neitzsche has fallen into the trap of believing what people say publicly about a taboo subject.
I’ve read all of the 9 Little House books by Laura Ingalls Wilder, and Rose is only a toddler in the last of them, The First Four Years.
The book you’re referring to must be one of the 3 sequels written by Roger Lea McBride, whom Rose designated as the heir to the book rights. As such it’s not at all reflective of the original books, which have no mention of sex; in them, Laura and Almanzo get married and have a baby with hardly a mention of a hug or kiss.
Ah, yes, my bad. It was a book written from Rose’s first-person perspective too.
I don’t think Qadgop would have much inside information about this, but Jackmanii might.
However, I don’t think the “Oh, we didn’t know we had to do that!” thing is an urban legend, even nowadays. My old pastor and his wife have said that they’ve had some rather interesting conversations with doctors in their area (which nowadays is Tennessee; read into that whatever you may). Another I’ve read about is how the incidence of ER visits by women for surprise anal intercourse has skyrocketed in recent years, something they learned about (or HE did, anyway) from pornos.
Back in the 1980s, I worked with a woman who had 3 young children, and bragged about showing them X-rated movies because she felt it was a good way to teach them about sex. (One of my other friends said, “That’s not even the KIND of sex you want your kids to know about!”) Not surprisingly, I found out that she had been abused by a relative, and it had gotten in the newspaper. The abuser was not her father or her brother, and she was not named but everyone could figure out it was her from the information in the paper. I told my source, a HS classmate of hers, “That’s horrible!” and she replied, “No, it was probably her idea.”
wow
I could tell you some crazy stories about misuse of birth control pills - so why don’t I?
There was the couple who showed up at an infertility clinic, and one of her meds was Ortho-Novum 7/7/7. The doctor said, “Those are birth control pills” and she replied, “I know. My friend told me that if I skipped two every month, I would get pregnant, and I’ve been skipping two a month for a year and I’m still not pregnant.”
And there was the woman whose 3-month supply ran out in 5 weeks. How, you may ask? Well, you see, she was married and had two men on the side, and took a pill every time she had sex.
Or the woman who got pregnant on the Pill - because she had found, ahem, some OTHER way to take them, i.e. vaginally.
Or woman whose 6-month supply ran out in 3 months, because her husband was taking them too.
I delivered my share of babies, did infertility workups, counselled about birth control etc. during my career. The vast majority of those patients didn’t seem to have any basic knowledge deficit, but some did. Including the very first baby I ever delivered in1981, to a girl who just had turned 13. She’d had no idea what was going on. Truly sad and outrageous.
That’s where I saw the lack of knowledge, in the very young.
Not sure how much OB/fertility experience @Jackmannii has as a pathologist, possibly quite a bit. Hopefully he’ll weigh in. But I expect I delivered more babies than he did. I also worked in Planned Parenthood clinics for a time too.
About your second paragraph: At first reading, I was thinking that she was sent away at age 10 because SHE was pregnant! Whew, what a relief that she wasn’t.
Ca. 1950 when my mother was in HS, there was a girl who, by the end of the school year, 10th or 11th grade, was obviously pregnant. The family lived on a subsistence farm outside town, and when school resumed after Labor Day, she wasn’t there, not until a few weeks later when she told everyone that her mother had a surprise baby and she’d had a rough time and needed her to stay home and look after it. Everyone knew otherwise, but never talked about it.
I asked my mother about who the father might have been, and I don’t remember how she replied, but in short, she hinted that it was probably incest. 
I thought @Jackmanii was a family practitioner. I know that @DSeid is a pediatrician, or is s/he?
Correct, practicing pediatrician.
@Jackmannii has often said he is a pathologist.
I am but have no insight from my professional vantage point on this question.
I have a hard time imagining humans who have gone through puberty not figuring out that tab A in slot B was fun. Evolution required that.
But evolution does not require knowledge of what results sometimes as a result of that.
Taking a birth control pill more than once a day is dangerous to your health!
In fact, being given full knowledge of the other end of the affair would probably disincline your average woman from participating in the first place. Ignorance is sometimes evolution’s ally.
Yet in most species, including humans, the consequence being more costly to the female incentivizes greater partner selectivity. Those behaviors can occur without conscious awareness of why they exist, and likely do in many species… but in humans I WAG that conscious knowledge of the result is part of it, and that effective birth control has impacted those behaviors as well.
…and yet here we are and people are still having babies because they want them.
Some women used it (taking 2 or 3 Pills in one day, after rape or unprotected sex) as Plan B before we had Plan B.
But humans differ from most other species in their ability to consciously plan for the long term. For most species, things “just happen” as time goes on. Even flying south in the fall or building a winter supply of honey are more instinctive than planned actions. Consequently, there is no need to understand longer-term consequences.
As I said, human instincts are atrophied because socializing and learning has substituted for a lot of it. This has made us more adaptable - for example, we don’t instinctively know what foods are good, we rely on one person trying and being told what is edible - thus allowing us to spread into unfamiliar environments more easily and having access to a broader range of foods. (Except, we still instinctively see what is putrid, and avoid it unless - for some of us - it’s blue cheese.)
The same goes for sex. Nobody needs to know that sex results in babies for the moment, just that it feels good. We have figured this result out long ago and passed that detail on to each other - usually - so those who do or don’t want children can take the necessary steps to effect that outcome.
I think that’s pretty common among mammals. Baby mammals learn from their mothers what is good to eat. Or from watching other members of their species. My father grew corn for many years, until his local squirrels learned that it was tasty, and then he couldn’t after that. I can give a lot of other squirrel examples. I’ve read that a major reason that most large carnivores don’t eat people is that ones who do tend not to rear cubs.
And while the time between sex and “everyone can tell she’s pregnant” is too long to for the connection to be obvious, the time between sex and “I feel different” is much shorter. (Like, I woke up the next morning and thought I was pregnant. Twice. Both times I was right. Another time I woke up and wondered if I might be pregnant, and that time my period was a month late. My college roommate got morning sickness two days after sex. YMMV, but the proto-placenta starts spitting out HCG as soon as it implants, and some women are sensitive to that.)
And as I said, in the days before mass media, people had more time to observe the world around them, and before mass-produced paper, fewer people relied on writing things down. Human memory is pretty good. (As an example they deduced details of seasonal celestial events and planetary movements long before writing, which obviously involved specific long-term observation and memory). With a bunch of goat herders sitting around contemplating life, it wasn’t hard to figure out over decades that a man having sex with a woman who is having periods leads to pregnancy. (and like small towns or high schools this century, nothing is private from the group) Particularly, over the years, the offspring tended to have a resemblance to the male involved. Humans were pretty good at connecting cause and effect. Plus, they got to see the effect with the goats, in a compressed timeframe. And as I said, only one thing generally goes in, and babies come out.
Whether that either translated to some individuals understanding the details (or either one or other not caring) is a different issue. I suspect we’ve been more reticent to tell children “adult things” in the last few centuries. Back when, everyone generally lived in one-room huts, and there were no TV’s or videos to distract kids, it was harder to hide these things. Indeed, the thing probably seriously missing today is children sitting around listening to adults and learning proper socialization.
As for teen pregnancy - teens of course realize that bad things happen to others, never them. I’m reminded of the time I dated a schoolteacher. We went to see the movie Amacord (it was a while ago). In one scene, they take the crazy uncle from the asylum on a picnic, he goes up a tree and when they try to climb up to get him, he drops rocks on their heads. The teen boy protagonists says “Ha ha, very funny Uncle. I’m coming up, it’s me, don’t drop a rock on my head… OWW! Why’d you do that?”
My date, who taught teens, says - “Typical teenager. He just saw half a dozen others get a rock to the head and just assumed it wouldn’t happen to him.”
The rest of that paragraph turned out to be far less … interesting … than this lead-up promised. 