1. Neutering can influence the dogs beavior, in both positive and negative ways. Some dogs get more insecure due to neutering resulting in more aggression. Read up about the subject, and please dont use USA websites only as they always tell you to do every possible medical intervention possible (they want to mak money).
2. If you think you should neuter your dog to avoid unwanted puppies, you should not ever consider taking a dog because you are NOT a responsible owner to begin with. Ever heard of a gate and a leash? Don't let your dogs wonder around the soi by themselves!
If you dont understand this, don't consider a dobie or even a jack russell. Go find another hobby.