re: I have to give a persuasive speech.

Giving out condoms in schools
Clean needle exchange programs
Welfare to work programs
Fair tax act
Occupy movement
Sex education in school
Normalizing homosexuality
Teacher sex scandals male vs. female
End of life decisions and medically supervised suicide for the terminally ill (action item could be Advanced Care Directives; DNR)

Any of these topics, pick a side and run with it. Always couch your strengths in the other person's defense.

And have fun. Public speaking classes were some of my favorite classes. I nearly always picked something off the wall and it was never something someone else was considering.