Carrie Underwood: I thought I was having a girl

Country music star Carrie Underwood's heart was set on having a baby girl when she fell pregnant, but now she can't imagine life without her son.

The musician and her husband Mike Fisher became the proud parents of Isaiah in February (15). Carrie discovered she was expecting after deciding to leave parenthood "in God's hands", so she was amazed to find she was having a baby.

"I was convinced I was expecting a girl," she recalled to Britain's Hello! magazine. "I had my heart set on it, which is partly why we decided to find out. I don't like surprises and there's no such thing as gender-neutral baby clothes. When we discovered we were expecting a healthy baby boy we were so excited. I wouldn't change him for the world. He's perfect and where before I couldn't imagine my life with him, I now can't imagine life without him."

Although the couple have no plans to expand their brood imminently, they do want more children. Mike would like to have four and while Carrie isn't ruling that out, she knows they will have a lot of adapting to do.

"I'm still figuring out how it will be when I take him on tour with me next year (16) and when I have more children," she said. "I have to be with them; that's not negotiable. We'll probably be figuring our way through this."

One thing that helps the pair is how strong their relationship is. They wed in 2010 after dating for two years and Carrie, 32, believes their romance works so well because they have differences.

"We're great together and we fill each other's gaps," she said. "I can't do numbers or add - it's not how my brain works - and money makes no sense, but Mike is very practical and figures are his thing. When we have meetings about finances, I zone out for two hours while he deals with it all."