Two human genes associated with breast and ovarian cancers cannot be patented because they are a product of nature, a federal judge ruled on Monday.

The American Civil Liberties Union (ACLU) and other groups sued in May to invalidate a patent on two genes held by Myriad Genetics on grounds those patents stifled the free flow of information and hampered research. Mutations on those genes are responsible for most cases of hereditary breast and ovarian cancers.

"Because the claimed isolated DNA is not markedly different from native DNA as it exists in nature, it constitutes unpatentable subject matter," U.S. District Judge Robert Sweet said in a 152-page written ruling. "Similarly, because the claimed comparisons of DNA sequences are abstract mental processes, they also constitute unpatentable subject matter," the judge ruled.

A representative from Myriad did not immediately respond to a request for comment.

During oral arguments held at Manhattan federal court last month, a lawyer for Myriad said patents have a positive impact on human health because they promote innovation.

"This is not nature's handiwork... this is the hard work of man," said Brian Poissant, a lawyer for Myriad. The lawsuit by the ACLU, the Association for Molecular Pathology, individual women and others was brought against the U.S. Patent and Trademark Office, Myriad Genetics and the University of Utah Research Foundation, which hold the patents on the BRCA1 and BRCA2 genes.