The role of the mother in childhood development was a frequent subject.

What will happen to her if the Porters ever find a way home, is a frequent subject of discussion.

Arms control has been a frequent subject in those meetings.

Making do had also been a frequent subject of lessons at the Academy.

The tension between the social order and an individual's drives is a frequent subject of his work.

Human and animal rights are frequent subjects in their lyrics.

Fear is a frequent subject of conversation among them.

Though Christopher wrote about many sports, his most frequent subject was baseball.

Unrequited love has been a frequent subject in popular culture.

This is a contentious issue and a frequent subject for debate.