You can make the same argument about a foetus in the womb.

Human beings terraforming the moon and Mars, would be like mother earth, giving birth to life in the universe, using us as the agent.

I'm starting to wonder how old you are and curious as to how many children you have bought
up?

So how does a proper grown up civilisation work then?

Your statement puzzles me somewhat, all the evidence I know, suggests the human race is a very young species, like Crocodiles are over 300 million years old as are sharks, how old do you think the human species is?

Perhaps part of the process of the human race growing up, is for us to put the earth back the way we found it.

As there is going on to be 7 billion of us, how do you propose we achieve this wonderful dream - a mass cull?

There is another route, is it an accident that we have evolved the ability to change the environment to an enormous degree?

Why not use this ability where it does not destroy a biosphere but creates one?

After all, nearly all of the raw materials are up there already, just waiting for us to get to work.