If they will have wants once they are born, bringing them to the world is justified. Your reasoning makes no sense to me.
Then why aren't you bringing in as many children into the world as you can? The average couple can have 12 children in their reproductive lives. Are you on track to reach that goal?
It was you who said that the important distinction is desire to live, I showed where that reasoning leads, and you agreed that it's nonsense. I have nothing more to say.
People that exist have wants.
I exist, yet the dozen other children my parents could have had don't. You can ask them if they want to have been born, but they don't have an opinion on the matter.
Which part of that do you have trouble with?