Now the entire idea to have sex with my sister revolts me. Not because she's ugly or anything. Most men I've spoke tell me she's really pretty actually, but I am not the one to judge for obvious reasons. Just the fact that she's my sister keeps me away, already, and my social relation with her is actually not relevant when it comes to that.
Now the reason why it's banned is to prevent inbreeding, since after all, the prime purpose of sex is only reproduction, and the full fun and romance we think about it was never what mother nature had in mind. That's just our own fantasy worked out together. Once exception in many laws is when a sibling is adopted. Of course when I have sex with my sister in blood the child would be an in-breed, but if I had sex with a sister by adoption (I don't but let's for now assume I have) a child that would come forth of it, would not be in-breed, since genes don't care about adoption laws after all.
Now when it comes to the romance and love, I don't think I should take an opinion. If the twins in the photo above are happy together, I should not condemn is, and if my condemning it could actually cause more damage than good to this sibling couple, I don't wanna be responsible for that. I can only hope that they are fully aware of the dangers of in-breeding if they actually have sex with each other, and that they should as such not opt for having children together (at least not on the natural way, since when it comes to adoption, siblings or not should not matter). The tweet does not say anything about how they have been thinking about the risks of in-breed children, since once you have sex, you can never be 100% sure no children will be there no matter how much birth control measures you take (well, there are a few that work 100% sure, but they are kinda drastic, and mostly only done when there is a very urgent medical reason to do so).
So I am a bit conflicted about this. No, I don't want siblings who are in love with each other to have their happiness denied to them, but I am worried about the effects of inbreeding too since history is full of very nasty things that are the result of inbreeding. This is one of those things in which two very important things are in conflict with each other.
