"We have a lot on our plates," says the singer of home life with Eddie Cibrian, 39, and his children Mason, 9, and Jake, 6, who live with the couple part-time. "But whenever I talk about kids, I'm like, 'Let's have one!' I have a lot of work to do now but I'm totally ready if it happens."
Timing aside, Rimes, 30, whose new album Spitfire is out June 4, is realistic about her dreams of being a mother.
"It took my mom 12 years to have me. I hope I don't have that [issue] but if I do, then a surrogate is something I've thought about," she says. "Eddie and I have also talked about adopting. My capacity to love a child doesn't stop at my own eggs, obviously!"
Rimes and Cibrian married in 2011, two years after separating from their respective spouses following an explosive, and highly publicized, affair.
"I felt like my life was falling apart," she says. "But now I feel settled. I'm proud of our great family. Eddie is an amazing father and I love my stepsons."
Still, Rimes says with a laugh, it would be nice to mix things up a bit when it comes time for a new arrival. "Testosterone is all around here so I need a little girl!"
For more from PEOPLE's interview and shoot with LeAnn, pick up the new issue on stands Friday
Additional reporting by MICHELE STUEVEN