I walked in on my daughter having sex with her cousin. They are both 14 years old. It happened in my sister's house in her double bed. I wasn't sure on how I should react but I told my sister and she just ignored it.

This isn't the first time that this has happened. They have had sex on numerous occasions and I have seen them kiss a few times. Me and my sister are the only people who know about their relationship so they only do this when they are either alone or if me or my sister are in the house. They have admitted that during sleep overs they have went into each other's rooms and spent the night there.

I asked them if they see anything wrong with their relationship and they said no. Before their sexual relationship they were pretty close. They were like best friends and I think they have confused that relationship with a more intimate one. They have told me that they love each other and that they want to continue their relationship and one-day get married.

How should I handle this, since I'm concerned about the incest part? Should I encourage their relationship? If not, what should I do from there?


2 Answers 2


First of all, the "how should I handle this" depends a lot on what your own concerns are. Is your concern the "cousin" part? or the "two 14 year olds" part? If the latter, is it specific aspect (are they mature enough to consistently use birth control?) or just general age-readiness for sex as a concept?

Once you sort out your concerns, the main and best thing is to talk to them - like adults.

  • Don't criticize (and make clear from the outset that you are not there to criticize) or patronize them.

  • Don't say things like "you're too young to know if you're in love".

  • Don't only concentrate on the negative. Merely list out pros and cons.

  • When you list your concerns, prompt them that they are more than welcome to address them in a rational way - if they see that you respect them acting like grown ups (e.g. being greatly relieved and pleased and proud if they DO use birth control), they are likely to be positively reinforced into acting more responsibly in general.

  • If you're concerned about the "cousin" part:

    My advice would be to relax - but inform them (see above on how you should approach communication with them).

    1. Plenty of human cultures have no issues with cousin-length-genetic-distance relationships. However, USA has a bit of a social stigma attached to the idea - which they should be aware of, lest they first encounter the stigma by getting insulted. YMMV based on where you are - in some states it may even be illegal for first cousins to marry.

    2. Modern medical science (especially genetic screening) makes the possible long-term concerns about genetic issues due to inbreeding less of an issue, assuming the unlikely outcome that they do marry and have kids eventually.

      However it's still something they must be made aware of as a risk. This article indicates that the risk increase of genetic issues is less than 2x that of non-related couple; although that is before genetic screening.

    3. On the pros side (for your to consider, AND for them to be told to demonstrate that you're not just at it to yell at them :)

      • being cousins, if they do marry, they would almost eliminate one of the biggest friction points for a married couple - "in-laws" incompatibility/interference/baggage/bad feelings.

      • being cousins, they are a LOT more likely to consider each others' feelings and care about each other as a person. So, while - as two 14 year olds - they are likely to fall out of love - they most likely won't act towards each other in a jerky/a-holish way that a random 14 year old dumping someone likely will.

      • being cousins who grew up together and close, they already know each others negative sides, to an extend, reducing unpleasant surprises that arise in and threaten any relationship.

      • plenty of people (including famous ones) had successful cousen marriage. Including (but not limited to) President John Adams, Charles Darwin, Einstein, Wernher von Braun, Jacob in the Bible, Abraham Maslow etc...)

  • If you're concerned that they are two 14 year olds having sex:

    1. First of all, treat it like any other 14 year olds sex concern. Most importantly, discuss:

      • STDs

      • Pregnancy prevension. If they aren't mature enough to 100% reliably use birth control, they aren't mature enough for sex. If they are (and were doing that before being discovered) it's less of a ground for worrying

    2. Discuss possible downsides if the relationship ends. Does your daughter realize how broken up she will be if her cousin falls out of love with her and moves on? Depending on her mental maturity level, she may be ready for it or not, and merely being 14 isn't a guarantee either way.

      • discuss that sex imposes possible negative outcomes if the relationship sours - jealousy, harder negative impact if one breaks things up, etc...

      • discuss what happens when they possibly have to separate, e.g. for college.

  • If you are concerned about "love and will get married" part:

    • First, many of your ancestors likely married about that age. So merely intending to marry isn't really a concern. They had less divorce rates than the late-marrying generation me-me-me, too (sorry, had to rimshot at the boomers :)

    • Second, as noted above, make sure they are mentally prepared for the eventuality that one of them changes their mind, and falls out of love. Don't tell them "this is guaranteed to happen" (even if chances are it will); but insist that they consider the idea and the consequences in advance.

    • Third - if they seem mature enough - look at the current research in terms of couples compatibility. There are several good books on the topic available and there was very good research into it recently. Find out the summaries, and show them and ask them if they think the research shows that they would be a likely-successful long term couple.

  • 3
    State laws vary concerning both 1st cousin marriage and 1st cousin sexual relationships.
    – user11394
    Commented May 19, 2015 at 0:26
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    @CreationEdge - meh. I'm almost certain that none of those laws would be left standing if someone bothered to bring it to SCOTUS as of 2015. I'm pretty sure none of them are actually enforced diligently.
    – user3143
    Commented May 19, 2015 at 4:18
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    @CreationEdge - edited
    – user3143
    Commented May 19, 2015 at 5:39
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    One note to consider re: They had less divorce rates - this is because divorce would leave women social pariahs and financially destitute, so a lot of women just put up with unhealthy relationships due to lack of a better option. The modern divorce rate isn't a negative thing.
    – Daenyth
    Commented Aug 3, 2017 at 11:52
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    @Daenyth - the modern no-fault divorce rates coupled with corrupt custody courts leave men social pariahs and many financially ruined and without access to their children. So, no, it's not a positive thing either in a lot of cases.
    – user3143
    Commented Aug 3, 2017 at 12:11

There are 2 (possible) issues here.


You could be concerned about the age. This does raise a few concerns:

  1. What happens if they break up?

    Will she be able to cope? A number of people around my age have been in serious committed, sexual relationships and haven't worked out - for a number of reasons.

    It often seems to be that those boys who will enter these relationships are likely to be the ones to be less committed and break it off. I may be making a generalisation here, but there could be a causal link between young sexual relationships, and the boy breaking it off (either cheating or moving on - perhaps getting bored).

  2. The law

    This may not be a concern for you. I don't know what country you live in, or what the custom is. However, I know that in my country, there is a shocking distinction made: Even if both are underage, the male has committed statutory rape. Now this may not seem like a big thing - who is going to follow it up. But what if she starts to use that over him (not saying she will)? She could claim rape, which is not a good place for a 14 year old boy to be in - a sex offender at that age does limit job prospects.

    However, this may not be an issue for you - you may feel it is acceptable or the law may be fine with this.

  3. Pregnancy, protection and STIs

    Pregnancy is not a lighthearted matter. Whether you agree with Abortion or not, it's a painful process (emotionally) and giving birth at 15 is really quite dangerous in some cases. Not only that, having a child is a big, big responsibility as you know, and still being at school when that happens is likely to limit her attention to education.

    Maybe this isn't an issue, and you would be happy with abortion? Next issue, protection.

    Protection links in between STIs and pregnancy. Condoms are typically the best preventative measure for both of these. The pill is a nice backup, but I wouldn't want to be going through treatment at that age.

    You can get them both tested together, but they're 14 years old. I don't wish to judge, but are they trustworthy, are they going to stay together, and is either likely to cheat? As mentioned above, at that age, it can be hard, and it is often the boy who will get bored and (maybe) move on.

    STIs are also no joke. Depending on where you live the treatment can be expensive and hard to access, and it's not something anyone needs. Interrupting education for hospital appointments is likely to be detrimental and also embarrassing if anyone finds out why.

  4. Revenge. This is unlikely, but if they break up, how would they react? If they are close enough to be sleeping together, one would hope they are close enough to have shared personal details with each other. Revenge is a real thing that does happen - is she sending explicit photographs that he could post online? Is he someone who would go around school saying she is easy? With the online world at everyone's fingertips, your reputation is important. Her mental state would not be great after a breakup with revenge.


  1. This is normal in a lot of cultures. There is a little concern about "inbred" genetic disorders, but as mentioned in other answers, there is genetic screening (although this links back to Abortion, so you may disagree).

  2. Two relationships. They are going to have 2 different relationships in a way. Aside from the (probably inevitable) breakup issues, they are going to know each other in one way, and then in a separate way. How will they behave around family? As a couple or as cousins? Going back to a breakup - my family is big on "BFGs", or "Big Family Get-Togethers". How would being forced together with your ex be? How would it be if your family are expecting you to be happy to see each other?

    I wouldn't want to be in that situation.

It's a difficult one this. You should still be the one deciding - you're her legal guardian and at 14 years old, it's likely you know best. However, I doubt you're going to be able to make the decision for them. My opinion - 14 years is too young to be making life changing (?) decisions. Especially with the added risk with their chosen activity. I'd also be concerned about the breakup. I'm sure they will think they will be together forever, and probably get married, but that doesn't mean they will.

I know my son wants to be with his girlfriend forever - and I believe they can (and probably will). But that doesn't mean there is no chance of a messy breakup, especially because of their current situation - BFGs are not going to help this.

My apologies if I've been stereotypical / offered my opinion too much. My observations are mainly formed from what I've seen at school, with people in young sexual relationships that don't work - and I don't want yet more people go through the process I've watched so many others go through (especially as I've supported a number of them).

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    FYI - modern science has determined that even first cousins, the genetic thing is not a big deal. I think repeated generations of constant inbreeding is what caused problems with European royal families, but not a big deal, risk wise, of the occasional dip into the family gene pool, apparently. nytimes.com/2002/04/04/us/… Commented Sep 21, 2016 at 21:47
  • @AndrewMattson yes, although only 3 generations are needed for significant problems, like sterility. Of course that isn't the case here. Until I answered this, I did not consider it to be inbreeding - in the U.K. first cousin marriage is completely legal.
    – Tim
    Commented Sep 22, 2016 at 8:30
  • Perhaps that was not the best term to use. It does seem to carry a negative connotation. Commented Sep 22, 2016 at 18:07
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    Excellent point about the institutionalised misandry in statutory rape laws. Commented Nov 22, 2018 at 23:36

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