This century truly is amazing to witness as incurable diseases slowly become reasonably within reach to tackle. A huge step from widely established symptom treatment into reaching right to the source/root cause.
I think lots of people would support a world in which it was illegal for Huntington's carriers to reproduce (or two people with recessive Huntington's alleles, whichever). That rule would stop an unimaginable amount of human suffering. But unfortunately that highly acceptable idea (I think) sits within a wider category that is extremely controversial, unpopular and dangerous.
People cannot be trusted to just outlaw Huntington's on its own, because the next politician will take power and outlaw some ethnic group they hate, arguing that there is precedence. Which is really annoying.
That is extremely unethical. Going off Wikipedia, most people with Huntington's start presenting symptoms from 30 to 50 years of age. Those are 30 years that they can live a normal fulfilling life.
Prohibiting people from having kids because their children may or may not live a shorter life is, as you pointed out, a slippery slope.
Have you seen a patient presenting with Huntington's? I wouldn't wish that suffering on my worst enemy.
The chance is 50% for every child of a person with Huntington's. Is it ethical to deliberately have children knowing that they have a 50% chance of of their lifespan being cut in half, then dying in unimaginable pain guaranteed? There is always a risk for birth defects, but this one is a _choice_. Some people knowingly choose this fate for their children instead of adopting - that feels so wrong to me.
Even ignoring the humanitarian side, think of the societal cost. Every patient needs expensive round-the-clock care in the later stages, families and friends watch their loved ones deteriorate. If I was born knowing I had an early expiration date with that fate, I'd certainly need therapy. It's completely preventable.
