Ethan says the family enjoys having the camera crew in the house. "It's been great fun from the beginning," he says. "We always felt like the worst thing that could happen is we have great home videos for the first years."
Right now, Casey and Ethan say they aren't worried about following in the footsteps of America's most famous parents of multiples, Jon and Kate Gosselin, who divorced after filming five seasons of TLC's Jon & Kate Plus 8.
"We feel like each family is really different, and we don't know their family or really anything about them," Casey says. "We just know the relationship we have and how our family works, and so we've decided to always be very open and honest with each other and keep our relationship strong. That's the most important thing."