I found this an interesting and somewhat strange perspective, and I decided to have a look around to see what other YA authors had to say. This is a quote from Sarah Ockler, author of TWENTY BOY SUMMER:
"Not every teen who has sex or experiments with drinking feels remorseful about it. Not every teen who has sex gets pregnant, gets someone pregnant, or contracts an STD. Not every teen who has sex does so while in a serious relationship. Not every teen who has sex outside of a relationship feels guilty, shameful, or regretful later on."
I'm still a teenager, and I'd say this quote applies to 95% of my teenaged friends. Most of them have had sex. Some became sexually active as early as freshman year, although late sophomore/early junior year seems to be the norm. None of my friends have ever been pregnant or contracted an STD. And, having spent a great deal of time talking with said friends about sex and relationships (hey, we're girls, it's what we do), I can confidently say that none of them regret their decision to become sexually active. Of course, I'm not claiming this is true for all teenagers. There are plenty of teens out there who probably regret having sex early in life, or who end up pregnant/infected. But in my experience, there are also teens who have satisfying, safe, and healthy sex lives. (Side note: my friends are all very self-confident people, which makes a huge difference when it comes to sex, because self-confident girls are less likely to have sex solely because of peer pressure.)
And as Sarah said, those teens don't necessarily feel shame. I think this is a hard thing for adults to accept, because we want children to remain innocent for as long as possible. But it's reality. Teens have sex, and sex, even at a young age, can have positive consequences as well as negative. I have friends who are in long-term relationships (5+ years). Sex is not detrimental to their emotional or physical well-being; on the contrary, sex enhances their relationships, and it's an important part of romantic intimacy.
There are people out there who believe (usually for religious reasons) that sex should only occur between a husband and wife. I completely understand this sentiment. I can respect such a belief, even if I don't necessarily hold it myself. So the real question is, what gives us the right (as authors) to shame teenagers who've made such decisions? Is it really our job to preach about whether or not teenaged sex is bad? Teens are smart, and we can tell when we're being preached to. Oftentimes, authors who try to insert morals into their stories come across as unprofessional, unsubtle, and just plain annoying.
For me, the key is separating your character's thoughts and feelings from your own. In other words, don't make your characters feel shame because you think they SHOULD feel shame. You have to get inside your protagonist's head. Would this distinctly unique, flawed character feel bad about having sex? Put your own ideas aside and try to see it from their point of view. If I'm writing about a character who grew up in a small conservative town, where her parents impressed upon her the importance of chastity, she would probably feel guilty about having sex as a teen. Shame isn't the message I personally want to send, but as the author I feel it's my job to forget about "messages" and write a story that's organic for the characters. And if one of my teenaged characters decides to have sex, I'm not going to "punish" them with pregnancy or an STD or emotional damage just to please parents. That being said, all actions should have consequences. If your story includes sex, there should be a reason. But those consequences (positive or negative) need to be natural for the established character.
And it's certainly true that not all teens have sex. Some choose to wait simply because they don't feel ready. My point is, whether or not your teenaged character has sex (and how he/she feels afterwards) should be determined not by your own personal beliefs but by the beliefs of your character.
When I read books, I want stories that are realistic. I don't care about the author's personal views; I care about believable characters, a strong plot, and authenticity, qualities I attempt to emulate in my own writing.