Can a table be both parent and child to another table? Newsdatabase with comments

[Smitche88]

I'm writing a school project where i have the following three tables:

users_tbl (t1), news_tbl (t2) and comments_tbl (t3).

news_tbl contains a foreign key(username) to users_tbl, and comments_tbl containes a foreign key (news_id) to news_tbl.

I'm not sure if t1 or t2 is the parent table and the two others is child tables, in case which one is it then?

Or if t1 and t2 is both parent and child tables to each other?

[Rabbit]

users is the "parent" of news. news is the "parent" of comments.