A federal judge in Brooklyn explained in a court memo released on Wednesday why he rejected a landlord’s attempt to use a child’s Hispanic ethnicity to argue for reduced damages in a lead poisoning case.

Judge Jack B. Weinstein ruled that the attempt violated federal law governing the use of statistical generalizations based on race or ethnicity, and forbid experts on both sides to discuss them.

A lawyer for Mark Kimpson, the landlord, was seeking to reduce the $2 million in damages awarded to the child and his mother after she sued over lead poisoning. A jury awarded the damages on July 10 after finding that the apartment the family rented from Mr. Kimpson contained lead-based paint that had not been properly removed or contained.

“Posed is the question,” Judge Weinstein wrote, “can statistics based on the ethnicity (in this case, ‘Hispanic’) of a child be relied upon to find a reduced likelihood of his obtaining higher education, resulting in reduced damages in a tort case? The answer is no.”