should i neuter cisco?

hi guys im in a bind i have cisco whos 13 weeks and i a Chihuahua 18 months old called charlie and charlie is neutered but im wondering would it cause problems if cisco wasnt?

I cannot see how this would cause a problem, having an unneutered male should be fine with another dog that is either neutered or spayed, are you planning to get Cisco neutered in the future ??

I have only ever had one dog at a time and Rocky was neutered by the rescue centre so this was out of my hands.

Cant see a problem if your other boy has been done.
I haven't and wont be getting Vinnie done, but if you do its best to wait until 18 months/ 2 years, so can mature.  

I don't neuter, so unless he medically needed it i wouldn't neuter him

no.

If they are both getting on ok then there's no need to neuter right now. If you want to at a later date when Cisco is fully mature, that's a different matter.