We have 5 children, 2 bio & 3 adopted. They are 18, 16, 6, 4 & 3. All 3 of our adoptions are extremely open. Our children know that they grew in their Birth Moms tummys & even know who grew in whose tummy! LOL They know that our bio children grew in my tummy. They know their birth siblings. We have always talked about their adoption as we talk about anything. Very openly. Our 6 year old understands the circumstances of her adoption. I haven't yet to explain why she has 2 YOUNGER sibs though!
We explain it to them in a way they can understand for their age. As the questions come up, we answer them honestly. We talk about their birth families like we talk about the rest of the family, Aunts, Uncles, cousins, etc.
We feel the earlier the better!
GOOD LUCK!
Deb