If something can't be achieved naturally, then it probably isn't supposed to be done

This one sentence can cover so many things, some of which I agree with and others that I don't, but for this question what is your gut feeling most of the time, regardless of subject?

Also the term natural meaning without human intervention or inventions that make unnatural things possible, such as medical interventions, use of man made machines, etc.

For example (I don't agree or disagree with these statements, they are just a few out of hundreds of possible examples):

We cannot naturally bring back prehistoric animals, so it probably isn't supposed to be done.

We cannot naturally make a woman give birth before her body does, so it (inducing labour) probably isn't supposed to be done.

We cannot naturally change our eye colour, so it probably isn't supposed to be done.

We cannot naturally (or any way as of yet) bring people back from the dead, so it probably isn't supposed to be done.

We cannot naturally manufacture plastic items, so it probably isn't supposed to be done.

I know this question is broad and has a lot of variables. What raised this question for me was thinking about the what ifs of if we hadn't made inventions to for instance do a lot of things to improve human pleasure, but with very little regard for nature or preserving the environment. Most could easily agree that we cannot naturally do these things that harm the environment so much, so they probably aren't supposed to be done. But, when you ask the same type of question with a different subject and think about it you could come to a completely different conclusion, for example most would disagree with the statement we cannot naturally perform heart surgery to save someone's life, so it probably isn't supposed to be done.

So what do you think... if something cannot be done naturally it probbaly isn't or is supposed to be done?