Christian Science practitioners.

If you are a Christian Science practitioner, the services you perform in the exercise of your profession are a trade or business unless you were granted an exemption from coverage under section 1402(e) of the Code, and you did not revoke such exemption in accordance with section 1704(b) of the Tax Reform Act of 1986. An exemption cannot be granted if you filed a valid waiver certificate under the provisions that apply to taxable years ending before 1968. [55 FR 7311, Mar. 1, 1990]