In the 1980 case Little v. Streater, the U.S. Supreme Court ruled that a state must provide free blood tests to indigent defendants in paternity cases if such evidence is crucial to their defense. The case involved an unemployed man named James Little who was accused of fathering a child out of wedlock and subsequently sued for child support by Barbara Streater. Unable to afford a blood test which could potentially prove his innocence, Little argued that Connecticut's refusal to pay for it violated his right to due process under the Fourteenth Amendment as he was denied access to critical evidence because of poverty. The court agreed with him unanimously (9-0), stating that when such scientific proof is available and can be decisive on issues like paternity, states cannot deny it based on inability to pay.

In the dissenting opinion for Little v. Streater, Justice William Rehnquist disagreed with the majority's decision that Connecticut's refusal to pay for blood tests in paternity cases violated equal protection rights. He argued that there was no constitutional right to free scientific testing and believed it was not a state’s responsibility to provide such services. Furthermore, he contended that the majority had failed to demonstrate how this policy disproportionately affected indigent defendants or why they should be treated differently from other civil litigants who also could not afford expert assistance. Lastly, he expressed concern about potential financial burdens on states if they were required to fund these types of services.