A few questions about the 1960s culture?

So, watching my bootlegged episodes of The Wonder Years, which chronicled the fictitious life of Kevin Arnold (Fred Savage) from 1968 to 1973, I've come across two questions:

1) In the second episode, sex ed was said to start in public high schools in 1968. Is this true? In addition, the textbook shown as being used was "Health and Human Sexuality." Was this an actual book students were used, and does anyone know by whom it was written?

2) Were these classes originally taught by the respective genders' gym teachers?

Lastly, my high school history teacher mentioned a few years ago that near the end of his life, LBJ felt exhausted by the tug of the Vietnam conflict, between the 'hawks' and the 'doves;' those for and against the war, respectively. He further noted that there was a poster/photograph he recalled seeing of President Johnson near the end of his life with long hair and the caption along the lines of "If you can't be 'em, join 'em."

3) Can anyone verify this picture's existence, preferably with an image link?

Thanks for any help, folks. That last question has particularly intrigued me for the past six years.

Kegan