Our state schools do a maturation clinic for 9 year olds (boys and girls), then address reproduction in health classes from 7th grade on, including instruction on how to use a condom in 10th Grade (signed parental release required).  I think it is good.  Reproductive health is like digestive health, you need an understanding of how the organs work.  But parents are obligated to provide the framework of values, the social and relationship circumstances in which sexual activity is appropriate.  It is not appropriate for schools to address those issues.