Second, you need to understand what your children already understand and how they have interpreted it. Third, you need to understand their developmental capability in order to give them just enough information to expand their thinking without losing their interest or attention. I have come to thinking about how and when children understand adoption through my work and research over the last 20 years in how children understand sex and birth. As I have studied the field of adoption and talked to children about it, and especially as I studied the work of David Brodzinsky and his colleagues, I have seen dramatic evidence that the process of understanding not only parallels the process of understanding sex and birth, it is intimately tied to it. This makes a lot of sense, because children begin their interest in sexuality as preschoolers when they talk about babies and where they come from.
Young children are egocentric and concrete.
Let's go back to what I first suggested. Most of us have strong feelings, emotional and ethical, regarding sexuality and adoption. First we must examine these and be clear about our goals for our children, Children, even and perhaps especially very young ones, will understand the feelings associated with the discussion of a subject long before they can clearly understand the details. Often parents have a lot of conflicted feelings on these subjects. It is important to identify your own feelings so you can clearly distinguish when you are discussing your feelings and when you are discussing facts when talking to your child.