1. A parent shall support beyond the age of majority his or her child with a handicap until the child is no longer handicapped or until the child becomes self-supporting. The handicap of the child must have occurred before the age of majority for this duty to apply.
2. For the purposes of this section, a child is self-supporting if the child receives public assistance beyond the age of majority and that assistance is sufficient to meet the child’s needs.
3. This section does not impair or otherwise affect the eligibility of a person with a handicap to receive benefits from a source other than his or her parents.
4. As used in this section, “handicap” means an inability to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months.