Please always do your own fact checking.
Below is Margaret Sanger's own autobiography: Margaret Sanger: An Autobiography.
The following quote below is 100% accurate:
"I accepted an invitation to talk to the women's branch of the Ku Klux Klan...I saw through the door dim figures parading with banners and illuminated crosses...I was escorted to the platform, was introduced, and began to speak...In the end, through simple illustrations I believed I had accomplished my purpose. A dozen invitations to speak to similar groups were proffered." (Margaret Sanger: An Autobiography, P.366)