When you don't know where to start, the beginning is always a good place to try.
I was born into a Catholic family in the mid-1980s. My father was the eldest of five children in a very Catholic family with a stay-at-home saint of a mother and an Army Vet father who worked in a factory. He met my mother after she'd endured actual Catholic school, having been raised as the youngest of five siblings with parents sleeping in separate beds. They were both virgins on their wedding night -- good for them, I guess -- and one of the old family scandals was that my aunt (mother's sister) tried to claim my mother wasn't a virgin when they got married, and my father would always say: "Did she want to see the bloody bedsheets??" This was the unspoken expectation I grew up with even before I knew what the term "virgin" even meant.
Which, by the way, I didn't understand until 7th grade when someone asked me if I was a virgin. I thought it was a type of religion or nationality, so I said no, which surprised them enough to explain to me what a virgin was. Enlightenment occurred.
My mother didn't teach me about my period. She also didn't teach me how to ride my bike, shave my legs, or get a driver's license -- in a lot of ways, my parents dropped the ball in raising me and my siblings. It's important to acknowledge that they were wonderful in a lot of ways, too, but I learned a lot about what not to do by the time I had a child of my own.
Perhaps needless to say, I knew nothing about sex by the time it happened. I learned how to use pads and tampons independently. I learned about orgasms on my own. I went to my first pelvic exam after my first sexual encounter, alone. I was raised to believe that sex, especially before marriage, was wrong. God would hate me, I would burn in hell, and worst of all... my family would disown me. I grew up absolutely believing I would be a failure if I slept with a man outside of marriage.
It's not that I disagree with the general idea that physical intimacy is a sacred activity -- one which should be reserved for a partner we feel close to, safe with, and care deeply about. Being selective in sexual partners is not a bad thing at all. But teaching your child to believe that having sex with a trusted partner to whom they feel deeply devoted would earn them an eternity in Hell does something awful to that young person forever.
I should know.
I cried the first time I had sex with my husband -- the only man I've ever been with like that. I felt a deep sense of betrayal to my family, even though I'd been responsible and chosen well. In Catholicism -- much like in other Christianity-based religions -- the lesson was never about learning how to be selective: it was about control. Particularly of women. It was a core belief ingrained into my psyche that my crime would not only grant me eternal damnation, but would also ostracize me from my family.
This was only the beginning of my sexual/intimacy problems... but hardly insignificant.