Wormholes simply are not possible for more than a microfraction of a second.
The conjecture that a singularity could pinch off and connect to another singularity somewhere else in space has no basis in reality. It is a mathematical construct born of the Rubber Fabric drawings of Spacetime. You've seen the drawings before that depict a black hole in space. It is a gaping hole heading down from a flat sheet of space drawn as a grid. This is not an accurate dipiction of Space, it's just a simple depiction of one plane of space, instead of a 3D look.
People started fudging with these drawings and asked, "Where does the well go to? Could it maybe connect with another well somewhere else in space? What if we fudge our formulas a bit and see what happens?"
Here's the real skinny: Any singularity by definition is a Dead End. It is a point in space where mass becomes so dense that the gravitational pull on photons is too great for their escape. It is just a major gravitational well. If two of these were in proximity, I don't care if it is through local space or the imaginary wormhole, the singularities would quickly become one. If they are close enough to interact with common space, they would quickly merge.
Sadly, scientists let their Sci-Fi wishes cloud their lines of inquiry. They really WANT timetravel and instantaneous travel and faster than light movement to be a reality. So they LOOK for these results. Which violates the scientific method. Any study of cosmology will have you stumbling all over examples of this. First they created wormholes with wishful thinking, then they looked for ways that these wormholes could be navigated (I.E. rotating and doughnut singularities). Then they talk about all the cool effects of flying through a wormhole. They skip way too fast over the mere existence of them and jump to our interaction with them. The move from Science to Sci-Fi.
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