First things first: the question really is whether an entity is going to do you any good at all. From a liability perspective, keep in mind that anything you do is your personal problem; putting your medical practice into a corporation won’t shield you from your own malpractice. But it could, for example, shield you from your employee’s malpractice, or your file clerk’s sexual harassment claim against a fellow doctor. And it may also shield you from your partner’s malpractice. So there are upsides. Some states, like California (where I practice), restrict the use of certain entities by professionals. The term “professional” itself has some grey area. Typically, professionals required to have a certain education, training, and experience aren’t permitted to use an LLC for their business (in California). So lawyers, doctors, etc. will generally use a corporation, though certain professions, like lawyers, have other specific partnership entities available to them. Others, like real estate appraisers, are still permitted to use an LLC. There may also be tax reasons, as a professional, to put your business into an entity. There’s much to consider.
Yes. Well, you have the same liability protection as a multi-member LLC. There will be some specific exceptions. For example, if you are personally negligent or you are responsible for your company's payroll tax obligations, then you'll be exposed to personal liability. But being a single-member LLC won't change that. There may be instances where being in a partnership may change an outcome in an insolvency situation and certain specific other circumstances.
In its most basic terms, this is the money (or sometimes the assets, like equipment) you put into your business. It differs from a loan in that it doesn’t accrue interest payable to you. If you put money into your corporation or LLC (or partnership), then the return of that money to you as you start to distribute money to you, is non-taxable.
No, a capital contribution isn't necessary. But typically you would, and should, make one. You would because there’s almost no way to start a business with zero invested in it. And you should because if your corporation is “under-capitalized”, then you could be exposing yourself and fellow shareholders or members to personal liability, making the formation of the entity a waste of time and money. And it takes more than $1.00 to protect yourself (but nice try).
In very lay terms, a K-1 is the partnership equivalent of an employee’s W-2 or a contractor’s 1099. Because a partnership doesn’t generally pay taxes of its own, it issues a form to each of its partners, telling the partners what each of them needs to put on his/her/its own tax return. LLCs taxed as a partnership (the default for multiple-member LLCs) issue K-1s. For more on forming partnerships, here's an article. Or, if you prefer to be entertained, here's a video.
Well, if I was your mother, I’d say yes, that’s very complicated, and please just pay him for services rendered. But, as your lawyer, adding him is not that complicated. However, the result is that you’ve now turned what was essentially a sole proprietorship into a partnership, requiring tax returns, fiduciary duties, and ideally, a written partnership agreement for when you want to show your boyfriend the door.
Depending on what state your company is located in, this could be as simple as filing a single form with that state’s governing agency. In some states, this may be more complicated, but there’s always a way. Keep in mind, by converting the entity, you will likely have to get it a new Tax ID Number, since it’s now a different entity. If there’s a partnership agreement, or certain rights with respect to voting or capital return, be careful about property transferring all of that over. Consult with tax and legal counsel.