The case before the U.S. 6th Circuit Court of Appeals is one of several in the nation’s federal courts that challenge employer insurance requirements of President Barack Obama’s Affordable Care Act, also known as “Obamacare.”

Under the law, businesses with more than 50 employees must either provide some form of insurance to their employees or pay a penalty. Because contraception coverage is required, some business owners have objected on religious grounds.

The case Tuesday involves Autocam Corp. and Autocam Medical, Michigan companies that manufacture products for the auto and medical industries. Company owners John Kennedy and his family say providing health insurance with birth control coverage to their more than 600 U.S. employees violates their Roman Catholic faith.