I was just wondering because theres a 5 month old yorkie boy that's adorable but he's not yet neutered

I'm worried he would start marking. He hasn't at all at this point. I don't care if he marks outside just not in the house. Wow everyone's answers were so helpful but different..lol...Maybe it's a personality or social thing, meaning if they see other dogs do it they learn. Since Coco is a girl maybe he wouldnt since she squats?