Hilary Duff tells Access Hollywood she and her husband, Mike Comrie, are "literally obsessed" with their 9-month-old son, Luca. They are planning their first Christmas as a family, and it sounds like they have wrapped their worlds around the little guy.

Hilary is a dog lover who contributed to the book A Letter To My Dog: Notes To Our Best Friends, and she explains how her dogs have adjusted to Luca. She and Mike kicked the dogs out of bed a month before Luca was born, so they didn't immediately blame him for their eviction. Later, the dogs were given a blanket with Luca's scent from the hospital so they were able to get used to the little guy. It worked.

But as much as Hilary seems to be taking to motherhood, she's in no rush to add a second baby to the mix. “Mike and I are literally so obsessed with Luca. We’re like, ‘He’s perfect. We should just be one and done,’” Hilary said. “But I think once your baby starts getting older you miss that baby phase and you go in for round two. But I think maybe when [Luca's] 2 or 3?”

A lot of only children wish they had siblings, and some people with siblings wish they were only children. But babies always grow up, so if moms really want to stay in the baby phase all the time, maybe they should just keep adopting new ones. Or volunteer in a local hospital's maternity ward!

Sources: Access HollywoodPeople