The missionary position or man-on-top position is generally a sex position in which a woman lies on her back and a man lies on top of her while they face each other and engage in sexual intercourse or other sexual activity. Though commonly associated with heterosexual sexual activity, the sex position is also used by gay and lesbian couples.
This is a context that is definitely appropriate for children of all ages to read about. 
My statement is definitely incorrect because if a person thinks a toddler should be exposed to and educated about sex, there is something wrong with their sense of morality. Minors in their later years before adulthood should definitely experience sexual education, but there is definitely a cut-off point somewhere even if it is not unanimously agreed upon. I think the system struggled because it doesn't understand that young and impressionable minds should not be exposed to something they cannot even physically or mentally process until puberty. 
( z1 context :domain ( z2 this ) :ARG1-of ( z3 appropriate :ARG2 ( z4 read :ARG0 ( z5 child :age ( z6 all ) ) :ARG1 z1 ) :mod ( z7 definite ) ) )