When other Adoptive Parents are Morons

Specifically, a person with whom I work.  He stopped by my cube to congratulate me.  Which is fine, until he asked "Where did you get it?"  It? IT?  Ironically, that wasn't what ticked me off.
It was this...he went on to say that he and his wife adopted but couldn't adopt domestically because teenage mothers wouldn't choose parents over 40, so they had to go foreign.  *picking my jaw up off the floor*
I suppose I can chalk it up to yet another socially awkward engineer.  But that's giving him an excuse.  What I really want to know is how can you adopt and be so insensitive to the whole situation?