Moral dilemma for you.
You're a new mother, and you're raising your beautiful conjoined twins. They're about 4 right now, and are talking in full sentences. They both show signs of high learning capability, and you've successfully taught them both to read.
The doctor tells you he has some horrible news. Their circulatory system cannot support the two of them; there were some birth complications. In about ten years, their heart will fail and they'll both die. That's right, heart, singular. Their systems are far too closely interlocked to separate them leaving both alive.
However, if you were to kill one of them, the other would live just fine. The limbs of the other could be amputated, and the remaining child could live a healthy life. The legal precedent says that you can make this choice.
But you can't make this choice in ten years. You have to make it now. If the heart has to support both of them for any longer, then it'll become irreparably damaged, and the failure will happen whether one is killed or not.

What would you do?
Let it happen, and when the time comes, know that you could have stopped it?
Or kill one, and spend ten years knowing it could have lived?