The No Doubt singer has two sons - 6-year-old Kingston and 4-year-old Zuma - with husband Gavin Rossdale.
[Gwen Stefani with her husband Gavin Rossdale and with No Doubt]
Although Stefani wanted to expand her brood in 2010, she said that apparently, she didn't plan the timing well.
She told America's Marie Claire magazine: "I really, really, really wanted [another child] about two years ago. It didn't really work out. So I feel good with what we've got.
"Everything works out how it should. You can't plan everything, right? You can try."
Stefani – who recently described motherhood as "overwhelming" - continued to explain that despite their bickering, her sons have a lot of love for each other.
"From the moment they wake up, they start beating on each other," she said. "I never knew they would be so physical.
"They're just starting to play real well together, but with a lot of fighting. They do look out for each other – especially the little one, he really loves his big brother."
Watch No Doubt's music video for 'Settle Down' below: