Draka
Wonder Woman
If it's a genetic condition, then this implies it's hereditary. Wouldn't you want to know before you had kids whether you'd be passing an excruciating incurable debilitating disease on to them? Maybe it would convince you to have kids by in vitro with donor eggs. Maybe it would convince you not to have kids at all.
Even setting aside the potential for passing the disease on to my future kids, if I knew that I'd be dead or completely debilitated by the time they were 10 years old, say, I think I'd probably decide not to have children. And I think that if I had the opportunity to know whether this might be the case, I'd consider it my responsibility to find out.
Already have kids. That much is done. Do I want to know if I'm going to die horribly before them? Not really. Like I said, if was something possibly preventable that I could avoid by getting a double masectomy or hysterectomy or along those lines, then ok. I simply don't want to know about anything that will harshly debilitate and kill me. If it was something that couldn't be avoided and it would affect me greatly, I wouldn't want my life to become about that. I wouldn't want knowing to be in the back of my mind until such time as I do get whatever it is. I don't want my life to be about my death.