Newly appointed Environment Minister Shinjiro Koizumi, the third-youngest Cabinet minister in the postwar era, has been tapped by Prime Minister Shinzo Abe for his youth and popularity with the media and the public.

The 38-year-old son of former Prime Minister Junichiro Koizumi, the younger Koizumi has often been highlighted as a future prime ministerial candidate.

But as he takes up his new post, observers are keen to see whether he will break the traditional customs he has criticized — with their initial attention on whether he will take paternity leave to help raise his first child, expected early next year.