under age sex and the law

Under age sex and the law

A tricky question about under age sex and the law. My advice on the law but also about what is ethical and how we can learn from our mistakes.

I had a boyfriend who, when we first met, was 15 and I had just turned 18. I know I shouldn’t have gone out with a younger guy but he honestly seemed 18 when I met him, which was at my friends party when I was 17. I didn’t want to do anything sexual until he was 16 but he kept insisting and said none of his other girlfriends were this ‘frigid’. I was worried he would leave me so one time he masturbated me and then I did the same back. I regretted it after and ended things with him. Will I get into trouble for this?

It is against the law to have any kind of sex with a 15 year old and as an 18 year old you would be considered an adult and him a child. However, I think, in these circumstances, you would not get in trouble for this.

I’ll explain the law to you (which is really tricky to understand) but also about the guidelines for prosecutions. I’ve spoken to a solicitor about cases like this (I’ve had a few questions about this lately) so some of the advice about the law is what I learnt from him and also reading the Crown Prosecution Service guidelines. However, this is not legal advice. You could speak to a law centre, or a local solicitor who specialises in criminal law (and sexual offences) to get that.

The law and prosecutions

In the UK it’s against the law to have sex with anyone under the age of 16 and this is true even if the offender is also under 16 (but over 10). For young people who are under the age of 18 there are special considerations about whether it’s in the public interest to prosecute someone. 

Prosecutions of incidents like this tend to happen when some harm has been caused. Where there is:

  • abuse, 
  • no consent, 
  • where the younger person has got upset (or a parent has got upset)
  • there is a big difference in physical or emotional maturity
  • if one person is exerting power over the other person
  • if there’s (what some people call) ‘full’ sex and it was the older person ‘doing’ it.

I think in practice, a lot of these would probably apply to you too, even though you were 18. The Police don’t prosecute all potential crimes and they have a lot of discretion. So for these reasons, I don’t think that you are going to be in legal trouble here. 

Just as an FYI, if you did this and didn’t actually know, but just assumed he was over 16 then you could have had a ‘reasonable belief’ defence. However if you knew he was under 16 then that wouldn’t apply. 

Read more about sex and the law

This is one of the leading sex and relationships education websites. We need your support via Patreon or Donorbox. Just £1 a month would be amazing (if 0.1% of you did that we could employ 2 people full time).


If you were the one who was calling him frigid and making him feel like he had to have sex with you, then I think you would be more likely to be in trouble. However, in this case it was him doing this to you. 

It sounds like this is something he initiated and actually kind of coerced you into. So maybe this was sex that you either didn’t really want to have, or did not consent to. He could have been committing an offence against you — possibly a more serious offence. In cases where offences might have been committed against each other, the Police would more likely investigate the most serious offence. They would then interview who they see as a victim in order to get evidence. More likely, they wouldn’t investigate at all.

Is it right? 

It’s all pretty complicated and as you have pointed out in your question, it gets even more complicated when we think about who did something wrong here. There was coercion on his part, and on your part you could have maybe just said ‘nope’ when you found out he was 15. From your longer email it sounds like things are fine with him.

So what now? Well perhaps you need to find a way to be gentle with yourself about this. Yes you made a mistake, but also it’s a mistake that you were coerced into making. Instead of thinking so much about whether you have broken the law you could start to think about what you learnt about this. 

We all learn how to do sex and relationships from having sex and relationships (as well as from sex ed of course 💅🏻). So it’s okay to use this as a learning experience too. What does it mean to you to have a good ethical relationship with someone? How can you make sure that everything you do is as consensual as possible? 

You might also want to help other people learn from this. How does it affect your views on women, sex and society? What can we learn about the stigma and shame that women get around sex? 

Try my Teach Yourself Sex Ed course (it’s free).

Scroll down to leave a comment. I moderate all comments before they go live. Click here to ask me a question

Please give feedback and help me improve the website

© Justin Hancock, 2022

I hope you’ve found this website helpful. Now here are all the ways you can help us, if you can.

Would you like a BISH podcast? Would you buy merch? Where do you get your sex ed from? What do you think about people like Andrew Tate? If you like answering questions like this please take my survey. It won’t take you long and it would really help me out. Thanks if you can!

This is one of the leading sex and relationships education resources online. We need your funding, so can you become a member of our Patreon?

Or if Patreon isn’t your thing, you could make a one off or regular donation via Donorbox

If you a) are over 18 and b) have money, you might like my coaching service. So if you are struggling with sex, relationships, and you generally, you might find it really useful. It’s really effective and you may well only need one or two sessions. Find out more at my coaching page here.

Buy my book

You could also buy my Sex Ed Activity Book, a fun zine with over 50 worksheets to help you to work out how you can do sex, love, and you.

Stay in touch with Bish! Get an email every time I post an article. Or follow on Twitter (I post less on Instagram and TikTok because they take down sex education content!) The rest of the article continues below.

If you’re over 18 and really into sex ed I have a podcast you might like called Culture Sex Relationships.

If you are an educator please check out my very popular RSE resources at bishtraining.com

Justin Hancock has been a trained sex and relationships educator since 1999. In that time he’s taught and given advice about sex and relationships with thousands of young people in person and millions online. He’s a member of the World Association for Sexual Health.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.