The `New Year`s Eve` actress - who raises three-year-old adopted daughter Naleigh with husband Josh Kelley - explained the couple had spoken about becoming parents before they even got engaged, and they would be keen to give a home to child before trying for biological kids.
She said: "Josh and I started talking about it before we were even engaged. We have talked about having biological children as well, but we decided to adopt first. I`d like to adopt again."
The 33-year-old star admitted while she loved daughter Naleigh from the moment she was put into her arms, she struck up an immediate bond with Josh, which was "hard" for Katherine.
She added in an interview with Parent and Child magazine: "Anyone who doesn`t have experience with adoption wonders, `Does love for a child come through DNA?` I knew it didn`t.
"They`re yours. You love them the moment they`re put into your arms. Josh had to learn that, but he was so gracious and accepting.
"Naleigh felt really comfortable with Josh and they bonded quickly. It was harder for me. It was a struggle for me because all I wanted to do was bond with her. But it takes time for a child to trust this new situation and to trust you."