CHICAGO (AP) — Legislation aimed at fighting a silent epidemic of a contagious liver disease is being opposed by Illinois’ largest doctors group.

The Illinois State Medical Society is urging Gov. Bruce Rauner to veto a bill that would require doctors to offer hepatitis C tests to patients born between 1945 and 1965.

That’s been a national recommendation since 2012. The group says doctors don’t need lawmakers telling them to follow guidelines.

Chicago transplant surgeon Dr. Steven Flamm disagrees with the medical society. He says the legislation would raise awareness and thousands of Illinoisans carry the virus but don’t know it. Hepatitis C infection is a leading cause of liver transplants.

Rauner’s office says the governor “will carefully consider any legislation that crosses his desk.”