In the case of Sullivan, Secretary of Health and Human Services v. Zebley et al., 1989, the U.S. Supreme Court ruled on how disability is determined for children under the Supplemental Security Income (SSI) program. The court found that the Social Security Administration's method for determining childhood disability was more restrictive than Congress had intended when it established SSI in 1972. The administration used a list of impairments to determine eligibility; if a child’s condition did not match an impairment on this list exactly, they were deemed ineligible regardless of their actual ability to function normally. In contrast, adults could qualify as disabled even if their conditions didn't precisely match those listed but prevented them from working gainfully. This discrepancy led to a ruling in favor of Brian Zebley who had been denied benefits despite his severe mental and physical disabilities because his specific ailments weren’t listed among eligible impairments by SSA standards at that time.

In the dissenting opinion for Sullivan, Secretary of Health and Human Services v. Zebley et al., Justice Blackmun criticized the majority's decision to uphold a standard that he believed was too stringent for determining disability in children under the Social Security Act. He argued that this standard failed to consider multiple disabilities which, when combined, could be just as debilitating as a single qualifying impairment. Furthermore, he contended that it ignored Congress’s intent to provide benefits broadly to disabled children by requiring them to meet or equal criteria designed for adults. He also took issue with how functional limitations were assessed only at step three of the process rather than throughout all steps like in adult cases. Lastly, Justice Blackmun expressed concern about denying benefits based on an inability to show comparable severity without considering whether there are jobs available suitable for such individuals' age and condition.