Carol,
Do self employed persons under 18 pay self-employment taxes?
Yes, everyone, regardless of age, must pay self-employment tax on self-employed net income, with the exception of household employees (babysitters, lawn care, etc).
Household employees under the age of 18 are employees and therefore do not pay self-employment tax.
(Self employment tax is the same as Social Security and medicare taxes for self-employed people)
Fortunately, the employer of a household employee under age 18 does not have to pay the employment taxes (Social Security and Medicare tax) either.
Read more about household employees in IRS Publication 926 Household Employer’s Tax Guide at http://www.irs.gov/pub/irs-pdf/p926.pdf.
Carol Topp, CPA