Anyway, my advice is dangerous and I know little about tax law, but if you can afford to register an LLC for your projects, you definitely should. It's only a couple hundred bucks in most states and you can get tax ID numbers from the feds and the state. These are accepted in lieu of SSN and other personal tax identifiers. You can file as a disregarded entity and avoid most of the business-related tax overhead (as long as you register the LLC properly), and it will just be less confusing all around; the IRS won't have incongruent numbers for your parents, you won't get taxed outside of the correct bracket, and you don't have to have anyone's personal info floating around out there.