I know, like it used to be dobermans, then it was german shepherds, and now it's pit bulls. Within a few years it'll probably change to another dog (watch it be husky 

)
Pit bulls are just the "bad dog" people say because people have used them for dog fighting due to their strength, but in reality you can do that same thing with a german shepherd or a rottweiler, everyone is just beefing on pits right now when they are really super lovable.
It's just how you raise the dog.
But yes you need to get a fixed dog. I work with the animal shelter and you have no idea how much of a problem it is when people don't get them fixed. It is actually a law for some states that rescues can't adopt dogs or cats out unless they are fixed due to overpopulation and homeless animals.