The difference wrt kids is that you have an option to refuse care in the long run, eg by giving up kids for adoption. In the violinist example, if lets say a su

The difference wrt kids is that you have an option to refuse care in the long run, eg by giving up kids for adoption. In the violinist example, if lets say a suitable volunteer is available but needs time to come to the hospital, then yes, you need to stay attached for a short while and disconnecting would be immoral. But if this choice is not given to you, can you be expected to sacrifice an important chunk of your life for someone else? Otherwise, should you be compelled to donate one of your kidneys?