A participant may be granted a disability benefit if:
An employee shall be considered disabled only during the period for which the board determines, based upon the evidence listed below, that the employee is unable to reasonably perform the duties of his or her assigned position as a result of a physical or mental disability. This determination shall be based upon:
The board shall prescribe rules governing the filing, investigation, control, and supervision of disability claims. Costs incurred by a claimant in connection with completing a claim for disability benefits shall be paid (A) by the claimant, in the case of the one required medical examination, medical certificate, and employer's certificate and any other requirements generally imposed by the board on all disability benefit claimants; and (B) by the System, in the case of any additional medical examination or other additional requirement imposed on a particular claimant that is not imposed generally on all disability benefit claimants.
Pregnancy and childbirth shall be considered a disability.
The same application shall be used to determine eligibility for the calculation of disability benefits under subsection (a) or subsection (b) of Section 15-153.
40 ILCS 5/15-150