In the case of Lalli v. Lalli, 1978, the U.S Supreme Court was tasked with determining whether a New York law that required illegitimate children to obtain a court order declaring paternity during their father's lifetime in order to inherit from him violated the Equal Protection Clause of the Fourteenth Amendment. The plaintiff, an illegitimate child whose father had died without leaving a will and without any declaration of paternity made during his life, argued that this requirement unfairly discriminated against illegitimate children. However, by a narrow margin (5-4), the Supreme Court upheld the constitutionality of New York’s inheritance law on grounds it served legitimate state interests in promoting orderly disposition of property at death and avoiding fraudulent claims against estates. The ruling emphasized that while states cannot completely bar illegitimate children from inheriting from their fathers' estates or treat them differently for no reason whatsoever; they can impose certain procedural requirements as long as those requirements are reasonably related to legitimate state interests.

In the dissenting opinion for Lalli v. Lalli, Justice Brennan argued that the majority's decision to uphold New York's law requiring illegitimate children to obtain a court order of paternity during their father's lifetime in order to inherit from him was unconstitutional. He believed this requirement violated the Equal Protection Clause as it unjustly discriminated against illegitimate children by imposing an unreasonable burden on them not faced by legitimate ones. Furthermore, he contended that there were less restrictive means available for establishing paternity and protecting potential estates from fraudulent claims. The state could have allowed posthumous paternity suits or required clear and convincing evidence of paternity rather than an absolute ban after death which unfairly penalized innocent parties who may not have been able to establish their claim within their father’s lifetime due to circumstances beyond their control.