As the featured article list has grown, so too have its categories, to a current total of 28. They are broad and are intended to keep the page clean and readable (compare the more extensive categorisation at Wikipedia:Good articles). User:Carcharoth has recently done a "snapshot" of the categories, creating a bar chart (at left) and a pie chart sorting the featured articles by type, as of February 23, 2008.
The single biggest category is Biology and medicine, with 161 articles. Articles related to the tree of life, particularly mammals, birds, and dinosaurs, are its largest component. Wikiproject Dinosaurs deserves particular recognition for consistently bringing articles to FAC. User:TimVickers has brought a number of biology topics to featured standard, including core subjects such as DNA and evolution. User:Casliber has been a frequent nominator of birds and dinosaurs, and has also worked on tree of life topics at the Featured article review.
The second and third largest categories are Media and Music, with 159 and 153 articles, respectively. The former is swollen by numerous movie and television related articles, and the latter by articles on contemporary bands, albums, and songs. Geography and places and History—two categories that cover a large percentage of Wikipedia's overall content—round out the top five. Biographies, which are currently spread across categories, account for 401 FAs and would be the single largest topic type if categorized together.
Discussion on the composition of the featured article list has not been without controversy. The relative over-representation of popular culture has become an issue at the request page for Today's Featured Article (TFA). With an ever increasing number of FAs, articles are waiting longer to be on the main page, and some (barring a change in main page structure) are likely never to appear. Video games and other popular culture articles have thus been opposed as TFA candidates over topic balance concerns, often leading to argument (e.g. this nomination). The four FA list categories that primarily absorb popular culture—Media, Music, Sports and recreation, and Video games—account for approximately 500 of the FAs, more than a quarter of the total. Not all of these articles are on contemporary subjects, and definitions of what constitute "popular culture" vary, but the FA list is clearly heavy on articles related to current, popular media. This is perhaps best underscored by the smaller categories: Religion, mysticism and mythology, Philosophy and psychology, and Mathematics—categories of core encyclopedic interest— account for just 3% of the featured articles.