'pet topic' is a correct and usable phrase in written English.
It is used to refer to something that a person is particularly interested in or has strong opinions about. For example: "Political theory is my pet topic; I could talk about it all day."
Last but not least, they insist that immigration, the FN's pet topic since the 1980s, has to be curbed.
Long a pet topic of Bill Joy, Sun's co-founder and chief scientist, a host of distributed computing initiatives is being pursued within the company.
The ratings, Miles said, give him valuable tips about his own future instructors and have prompted at least one teacher at his school to "scale back a bit" on her tiresome discussions of a pet topic.
But in recent decades, rising unemployment, poor housing problems and the questioning of the presence of Islam in a secular state have made immigration a pet topic of the far-right.
In his news conference after the match, which he won, 6-4, 6-1, 3-1, after Wawrinka retired with an illness, Djokovic took the opportunity in responding to the first question to address his pet topic: The rain is a factor here in New York.
Immunology is somewhat of a pet topic for Parker.
What next?" It's just a pet favourite topic of mine, Paul.
The magazine's pet topics may be controversial, but they aren't self-regarding.
This led Mr. Rosenberg to another of his pet topics: the need to educate young people to appreciate art.
Like many of the government's pet topics, it could still be brought undone by public and expert opinion, and a few bad headlines.
But on the host's pet topics, like health care or John McCain, the listeners were much more conservative than other Republicans.
