Most young children do not understand the meaning of "being born" and they start to ask questions about it. This is a perfect opportunity to introduce the subject of where babies come from, how they get here, and how families are formed. This information is very valuable in helping your child understand adoption.
You will have to discuss with your child exactly what you will and will not reveal about their adoption. Many adoption workers advise parents to introduce the word "adoption" as early as possible (between 2 and 4 years) so your child will become comfortable with it. However, some child welfare experts believe that when children are placed for adoption before the age of 2 and are of the same race as the parents, there probably is no point in telling them about their adoption until they are at least 4 or 5 years old.