A teacher is, first and foremost, a professional, and his or her personal views do not matter. At work, he or she is simply a teacher.

Who your child's classmate's parents sleep with is none of your business. You'd have to be completely insane to think that this could somehow affect your child. 

 Thanks for this great response! ;) 

 This sounds like good advice... In just a couple of countries not in the west.