@LegoBaka
you'd be surprised on how people think.
I used to know a girl that told the married dude that she was cheating with that she was taking protection. She honestly believed that if she didn't want kids, she wouldn't get kids and was extremely surprised and upset when she got pregnant. And of course the jerk she was sleeping with was perfectly happy going bareback with a girl his daughter's age completely assuming that when she said she was talking protection, it meant pills or IUD.
oh and birth control is ancient. Hell people were using animal intestines & bladders as condoms centuries ago in our world. All sorts of stuff were used to try to block sperm from getting too close in the female body.