My one year old Chihuahua is jealous, what to do?

When ever I pet another dog or hold a small child, he will literally bark in their face or jump at them until I stop. He doesn't necessarily act aggressively but you can tell he is mad. He's not a mean dog, he has never bit anyone nor am I afraid that he will ever bite anyone. He's just a big baby and wants all the attention from me. I am afraid that I will never be able to have kids of my own because of his jealousy. What can I do to stop him from acting this way?