When we are out and about it never fails (I mean NEVER) that someone asks me how old the girls are.  They continue to be an almost indiscernable 1 inch difference in height and weigh the exact same.  They seriously look like fraternal twins....well identical twins to people who have had little contact with black children (seriously I have had this...a guy at Walgreens thought I was surprised to find out I was pregnant with identical twins)  Anyhow, the girls are always happy to chime in that they are 5 and 4 1/2 (emphasis on the 1/2).  So, inevitibly the next question is how far apart are they.  To which I answer 6 months.  Then most people (the ones that can do math in their head or know anything about biology) ask so are they biological sisters?, or are they cousins?, or what came today the simple "Are they sisters?".  Usually I just say yes and walk away as cofusion spreads across their face.  Today though as I was rounding hour 3 of waiting for our van repair with no quick exit in site I mispoke.  When the lady asked "Are they sisters?" I forgot the little ears around me.  I said, "they are not biological sisters but they are sisters."  To which Wuby had a very cofused look and said in a loud voice, "but mom, we ARE sisters!!!"  I tried to explain that I meant that she and Sifan had different Ethiopian mommies, but the term biological sister was lost on her 5 year old understanding.  I realized then that I needed to further change my approach to questions from strangers.  These questions have mulitplied exponentially since Sifan has come home.  The girls are IMPOSSIBLE to miss.  If you are not overtaken by their cuteness (I swear I am not looking through mom colored glasses ;) ) then they will try their darndest to engage you in a conversation.  Like I said, you cannot miss them, they will not let it happen.  This openness that the girls have with strangers seems to loosen strangers tongues, and they ask whatever is on their mind.  Usually I don't mind at all....as I am often the Queen of TMI without embarrasement.  I will answer those questions that are sometimes prefaced by "I know this might be an ignorant question" and the questions that are down right ignorant and really shouldn't be asked.  I alwasy answer with a smile and often take the time to educate a bit about adoption, the process, the function of my ovaries, Ethiopia, etc.   I realized today though that maybe I need to hold my tougue a bit until I relearn how to better answer some questions because above all MY CHILDREN'S feelings and ideas about themselves and their family are MUCH more important than my furthering a stranger's education about adoption or just scratching that itch of curiosity strangers may have. 
T & I and talked it out and decided that we would say that the girls are about a year apart so that the uncomfortalbe question of, are they sisters doesn't come up as much and that our answer will always be Yes, they are sisters, no need for explanation of biology.  Often this will suffice if I am by myself with the girls because it isn't a huge leap to think that they are my biological children....often it makes me laugh even when I try to discern what people are thinking when I take the boys and girls out together without T.  But the new philosophy is, let them wonder.