I work in early childhood education and I read these books with my kids. The 2 to 3 year olds love 'we belong together' and it's a fabulous book about families of all shapes and sizes. It's written in a way that really involves younger kids, and the pictures really grab their attention. 'I call my grandma nana' is not about children conceived in different ways, but is a beautiful story about the differences from family to family. I haven't read Mommy, Mama and Me but I've heard great things about it. All of these books are available on a website called Fishpond.com.au which is a great site.

We Belong Together: A Book About Adoption and Families
By Todd Parr

I Call My Grandma Nana
By Ashley Wolff

Mommy, Mama and Me
By Leslea Newman, Carol Thompson