When and how?

My dear friend is expecting her second child.  Her first born is one year older than 3.  We are all very excited for them, but it brings up an interesting dilema for us.  When and how do we tell 3 more information about what “being adopted” means? 

He has always known that he is “adopted”.  But, at three years old, he truly has no idea what that means.  He knows T and sees her several times a year, but doesn’t, can’t, understand fully who she is.  Can a three year old understand the term “birthmother”? 

I know this is the age when it is “normal” for children to begin to ask questions about where babies come from.  But, when that child has been adopted, it becomes a bit more complicated.  I expect any day to hear some form of the where-do-babies-come-from question.  But, it’s the NEXT question that makes me wonder when and how….

“Was I in your tummy??”  Obviously I will tell him, no.  But, do I stop there and wait for him to ask more questions?  Do I tell him he was in T’s tummy and explain, in my most basic way, that that is what adoption is?  Or is that too much all at once? 

I am by far not a perfect parent, and I know one of my faults is talking too much.  For example, I’m working on telling 3 what I expect one time, then expect him to obey.  So, I don’t want to avoid discussing the details that he is ready for, but I also don’t want to overload him with too much information.  According to most articles and books I’ve read by adoption experts, it boils down to the fact that each child is ready for differing amounts of information at different ages.  So, how do i know when 3 is ready?

Right now, I’m not sure.  So, I’ll continue to read and pray and be honest with him.  I love him too much to do anything else.