I have been a Eucharistic Minister for 12 years and never encountered this before. I was distributing the hosts and had a parent explicitly request a blessing for his young daughter. He then went to take the wine and asked the EM giving the wine to do the same.
What is the best way to handle something like this? Obviously I, as a lay person, cannot confer a blessing upon someone. But I also don't want to create a scene at communion by saying "sorry, Canon Law prohibits me from doing this."
edit: sorry...I just noticed the sticky on this. While I guess we can all agree on it being unacceptable for an EM to confer a blessing, my question pertains more to how to handle it if someone does present his or her child for a blessing from me.