I’ve formed an opinion of this episode over the years from watching the episode quite a few times and chatting Star Trek on the various message boards. The whole premise the episode boasts as a “prime directive” episode is just crap I think. Why does Archer have to commit to a decision right now? Why not take Phlox's findings back to the Inter-Species Medical Exchange and allow them to deliberate/validate? Come back later? Archer did give the Valikisians medicine that would give them an additional 10 years to find a cure, so the out of control rage in most comments are uncalled for I believe. No genocide was committed or allowed here. Loved Crewman Cutler and was looking forward to seeing more of her as the series progressed. So sad that was not allowed to happen. I also loved Phlox’s conversation/narration throughout this episode.
Archer agreed with Phlox for all the wrong reasons. Whether it was genetic or not is really irrelevant. I'm not a doctor or anything like that, but what difference does it make? Archer should have not made a planetary decision like this on one doctor’s findings. He should have withheld an untested and invalidated cure because of the catastrophic damage an error could cause. Not because "it's genetic".
If you really wanted a "Prime Directive episode" that lays the grounds for the necessity of guidance for a non-interference policy, Archer should have made the mistake and the results should have been catastrophic and devastating. His human compassion should have won the day! He should have disregarded Phlox’s recommendation and ordered him to administer the "cure". What does Archer’s decision teach us with regard to the need for "some directive"? Nothing.