Why do you assume that life created by scientists would be without spirit?
You claimed JWs teach there is a theological barrier, not merely a technical barrier to scientists creating life.
WT literature actually says the opposite: that creating life is a technical challenge but that scientists may be able to do it one day. And if they do JWs argue it only goes to show that intelligence is needed in order to create life.
I wonder where did you get the idea that JWs teach there is a theological barrier to scientists creating life? Did it ever state this in the literature? I am looking at the older books but I can't find any comment on those lines.