Comment by cozzyd

Disclaimer: I am not a theoretical physicist (but I am an experimental one...).

If the universe, at the time of the big bang, had no net charge to begin with, and charge is conserved, then it follows that we would have particles whose charge will on net cancel out, and therefore charge would be quantized in some reasonable way. Note that there are doubly charged particles (e.g Delta++) but they're not stable. Some theories do predict fractionally charged particles (millicharged is the term of art) but there is no experimental evidence.

Now, was the universe neutral to begin with? If it wasn't , then that would presumably leave a strong imprint on early universe cosmology. I believe that current measurements of galaxy structure formation, cosmic microwave background and big bang nucleosynthesis probably place extremely strong constraints on early universe neutrality, though there may be caveats I'm not aware of.