It might also be due to your age - a friend who was pregnant with her first baby at 35+ years of age was given a genetic counsellor even though she didn't want one, as far as I know all her scans were fine and her baby was hale and hearty and ready to take over the world. so if you are over 35 that might be the reason? or it might be a policy of where you are having your scans done that everyone sees a counsellor just in case there is a problem.