A controversial subject is a topic that is debated or disputed because people have different opinions about it and it can cause disagreement or conflict. Full definition
Today with have a guest article about the sometimes controversial subject of finding love with someone older than yourself. (penpals.be)
The school library media center shall have materials on hand that represent differing viewpoints on controversial subjects for information and research purposes. (hcps.org)
The third book featured some very controversial subject matter. (brennaaubrey.net)