[Ponyup]

I had mine neutered at 19 weeks. He hadn't started marking before he was fixed, but learned it after. He only marks outside though; & we have to remind him not too in Petsmart. Maybe you could teach him not too in the house, like training a puppy say no & take him outside. In petsmart when I see Logan lift his leg to pee I say uh-uh not inside & he stops. Occasionally I don't catch him in time & i have to clean up a little mess, but he never does it at home.