While you're right about knocking when the door is shut, OP never said what room their sister was in, and they could have been in the bathroom with the door slightly cracked open for all we know, hence why OP walked in on her.

Or they could share a room.

no one said sex specifically, in the sense you mean it. it could be less horrible than you think.

Exactly, they could be experimenting with hands or oral. I did that WAY earlier than having actual sex.

A 13-year-old may be old enough to have sexual desires, but at that age she's way too young to be acting on them. The parents definitely need to be told about this.

Because abstinence only is just oh so effective, amirite?

#24 a little self control never hurt anyone. Not saying wait for marriage or even legal age, but at 13 you should be figuring out how to kiss not find a clit. At that age it's entirely possible she doesn't understand how to protect herself from pregnancy or STIs either. My school didn't cover that until we were 14-15 and kids generally have a lot of nonsense mixed in with the facts, like peeing right after sex kills all the germs and semen.

32- Which is exactly why abstinence-only doesn't work. Short of locking them in their room, if teenagers really want to have sex, then they will. She needs to be discouraged from having sex because, yes, 13 is too young, but she also needs to know the facts about sex and be taught how to properly protect herself against STDs and pregnancy. I have a daughter and I would hate for her to be having sex when she's only 13. I would hate even more for her to be having unprotected sex at 13 and wind up catching an STD or getting pregnant because I only told her to stop having sex because she's too young, instead of telling her the facts about sex

sex Ed and STIs and teen pregnancy starts being taught in 5th grade.

32, that's exactly my point. Regardless of which age you think it's arbitrarily okay to start porking people, teens who are so inclined are going to act on those desires, regardless of what moral objections you or anyone else may have. Simply put, telling the kid anything to the effect of "13 is too young" or some such is pretty much guaranteed to achieve absolutely nothing. On the other hand, ensuring she knows about safe sex, understands why it's so important, and most importantly, knows she can count on your support rather than self-righteous judgement in case something does go wrong (after all, condoms and other contraceptives do occasionally fail), will go much further in keeping her as safe and healthy as possible.

Women also used to be sold as chattel. Just because something used to be socially acceptable doesn't mean it still should be.

#42, Not everywhere. At my school, I didn't learn anything but basic biology until high school. I learned about sex on my own in 6th grade.

44- Well said. Your reply to 32 is much better than mine. Alienating your child by making them feel like they are being judged rather than supported is one of the worst things a parent can do not only in a situation like this, but in general. It just causes kids to hide things from their parents because they feel like they can't or are afraid to talk to their parents, often causing them to get in more trouble than they would have if they could have just talked to their parents. I was lucky enough to have a mom that I felt like I could talk to about anything. My friends? Not so much. Guess who got themselves in more trouble, especially in high school.

@32 I don't know why you're getting so much shit. I took your comment to mean "she needs to be educated" and not "she needs to practice abstinence" as everyone else did.

ha-ha alienating them or not. if the child gets in trouble they alienate themself, if a child doesnt confide in there parent, or trust them, its the kids fault. respect your elders, and do what you know it right.

In Wisconsin this is illegal. And it's stupid. A teacher mentioning condoms or birth control was illegal. I never even learned about stds until I was a senior

Never said she should have all the sex she wants. My issue is with everyone acting shocked at her age, even claiming our society is so sexualized it causes it. It's ridiculous. Puberty starts those feelings, guess when it usually hits? That's why safe sex talk is so important that young. Acting like its so ridiculous they have feelings like that so young seems more harmful than good to me.

44, I wish I could thumb you up more than once. This. You can't stop determined teens from doing it, but you can educate them as well as possible so they don't expose themselves to unnecessary risks while doing so. Also, if they are well informed they will actually have less inclination to try out everything at once than when everything involving genitals is just a huge mess of forbidden secrets.

@68 it's not always the kids fault if they weren't taught right from wrong or if they are alienated from talking to their parents about sex. Especially if the parents have yelled at them for, let's say catching them making out, which would cause the kid to be too scared to talk to the parent in fear of being in trouble. Or it could be that the kid asked their parent a question about sex and the parent refused to answer or told them it was too awkward to talk about, which would make any kid think they couldn't go to their parents. So sometimes it actually can be the parents fault.

#44 - I largely agree: at the end of the day, teenagers are people, and people are going to do what they're going to do. The best you can do is give them the facts of what they're getting into - and direct them to the appropriate contraceptives. However, I think you need to be careful of what you mean by "making it clear that they're able to rely on your support." There's a big difference between "we'll never abandon you, no matter what mistakes you may make" and "we will shield you from any and all consequences of your own foolish or immature decisions." OP isn't self-righteous to be concerned. We tend to be self-centred as children and teens and don't realise that our actions affect more than just ourselves (and yes, plenty of adults are like this too, but at least kids/teens have the justification of developing bodies and minds...). I have met more than a few teenagers whose attitude on unplanned pregnancy is "well, it's the parents' responsibility to take care of their grandchild while their kid gets on with their life." This is particularly worrying, as it's more or less backed up by society itself, with parents who refuse to "step in" when their teenager is incapable of caring for their own children usually viewed in a negative light). So the parents of teen parents are landed with additional childcare responsibility, and you can just bet that any siblings are going to be drafted in to help as well, not to mention the fact that the grandchild will probably dominate the household in terms of time and money, at the siblings' expense. I sometimes think we need to stress that side of things rather than just yelling "TEEN PARENTS ARE A DISGRACE"! or "YOU'LL BE RIDDLED WITH STDs"! over and over again. While many teens aren't good at spotting the big picture right off the bat, most will understand it once it's pointed out to them.

parents would talk about with there kid, if the kid wanted them to. if they don't see anything that leads them to believe the child is doing sexual things, they feel no need to talk about it

Not all parents do. There was just a FML not too long ago that the parents thought the sibling should do the talk rather than them. Some are the people trying to make sure abstinence-only education is the only thing taught. You can't say it can't be parents themselves refusing to educate kids, it's just not always true.

Also, you should start educating kids before they are sexually active so they know the risks and what they are doing going into it.

You don't even need to shave completely. Maybe she was just trimming, and using scissors alone is fine for that.

@33 That depends on where they are and how old the boyfriend is. I've never heard of any laws that state two underage people are not allowed to have sex. Then again, there are a lot of places in the world with lots of different laws.

it is illegal, you only pay a fine

Age of consent is 16 in the UK. Below that age you're not able to consent, even if it's with another under 16. I mean, no one ever gets arrested for it....but it is technically illegal.