Working through Schaum's German Grammar and they ask to turn "Ist das dein Kind" into the plural. The answer:

Sind das deine Kinder.

Why isn't it "Sind die deine Kinder" or "Sind sie deine Kinder", likewise, it's "Ist das dein Hund" versus "ist er dein Hund".

In this case gender is not followed - are there others?