Mom & Daughter Give Birth On Same Day

Here's a snippit from a story out of Knoxville, TN about a mother and daughter giving birth on the same day. Can you follow it?

...Kirsten, Erika's mother, gave birth to baby Gus. Two hours later, Erika had baby Ethan. That makes Gus, Erika's brother, and Ethan, Kirsten's grandson. That means Gus is Ethan's uncle, which is pretty amazing considering Gus is only two hours older...