I cannot agree more with Nelle, Trillian and others who have made similar points. For me, personally, there was no 'reason' to need to 'know' my body - my cycles have been whacky since I started puberty - no 28 days, regular, here. I wasn't trying to have a baby, I didn't care - AF just arrived whenever she felt like it, went on her merry way and I never paid attention. Falling pg for me involved no more 'thinking' or researching or learning about my body, than ceasing the Pill and carrying on as normal. I didn't even know I was pg until a routine urine scan for a completely unrelated condition was done at hospital one morning, and it was a huge surprise to me as I'd had what I assumed was AF just a couple of weeks before - then a dating scan confirmed I was almost into my second trimester. I'd had my 'period', no symptoms, no clue. If I'd suddenly grown a bump and done a test at home, I would have thought I was about 8 weeks behind what I really was, kwim?
If not for BB, I'd still have no clue about how my body works. Most women I know IRL are in the 'doctor knows best, he studied this at uni after all' camp, and so was I until stumbling across BB for something unrelated. Medical staff play a huge role in keeping us conditioned not to question - the way I was treated during my third pregnancy (with DD2) left me constantly feeling like I was bashing my head against a wall, or going crazy, because I was treated as a 'difficult' 'hippie' who just didn't like 'being told what to do' without having any real basis for my disagreement with my carers. If not for BB, I'd have simply gone along with whatever they suggested, not questioning, not caring, because I knew nothing and didn't feel that I needed to - I had midwives with training and experience to tell me what was going on, a few books to read on my own time, and an uncomplicated conception, pregnancy and delivery. Why clutter my head with useless info or stress myself about different methods when the 'traditional' ones would have worked just fine? Most people think like this, and while it's sad, I can absolutely understand that POV, though it frustrates me now that I am 'enlightened'.

It's our entire society - I don't blame women as individuals for being uninformed or seeming to 'not care' or know how their bodies work. If they're anything like me, it took no effort to get pg and takes no effort to grow a baby, it just happens, and the doctor will help get it out when the time comes (when they say, and they must be right because they see pregnant women every day of their lives). It's why I now refer my friends to BB when I see something I disagree with happening, because I want them to have the opportunity to learn, but I don't want to force it upon them.