Physician paid to consult/lecture last few years. Now about to see patients in an office she is renting, no employees. Is she a sole proprietor? Need EIN? Thanks!

Yes, unless she elects to have a corporation. You don't need to have an EIN, unless you meet certain criteria.

If you’re a sole proprietor, you must have an EIN to:

• hire employees
• have a Keogh or Solo 401(k) retirement plan,
• buy or inherit an existing business that you operate as a sole proprietorship
• incorporate or form a partnership or limited liability company, or
• file for bankruptcy.

Also, some banks require you to have an EIN before they’ll set up a bank account for your business.