While most students might argue that Barbie is a negative role model for young women because of her unrealistic proportions and seemingly vapid personality, a personality that can be deduced from advertising through the years, you could argue that, in fact, Barbie represents something positive for the female. You can discuss different movements in Barbie's history, including her job as a doctor or a pilot, as opposed to a model or a flight attendant. You can look at Barbie through the years and discuss the development of her role-model status.
While abortion is an overdone topic for persuasive speeches, you can focus on a different aspect of the social issue: RU-486, also known as the abortion pill. This pill, which is available to some women in the United States, is successful in ending pregnancies up to the end of the second month. Your speech can take either side of the legality issue, focusing on the pill's side effects, its consequences within society, and its accessibility.
For your persuasive speech, you could argue for an increase in cremations in the United States as opposed to traditional burials. Find statistics about the death rate of Americans, how much space is already occupied by cemeteries, and how much space is available for the expansion of cemeteries. You could stress how cremation is inexpensive compared to burials and how it requires almost no space for the dead, a reality that solves overcrowding in cemeteries. Be sure to focus on the religious aspect of burials; see if you can find evidence to support cremation in religious texts.
You could attempt to persuade your class that Title IX in schools is outdated and should be abolished. Because of Title IX, schools create scholarships for female athletes to play golf and other sports so that they can justify giving scholarships to male athletes for football and soccer, even though the golf scholarships are largely regarded as being a joke. Argue that Title IX should be abolished and replaced with a system that creates legitimate opportunities for female athletes. Ensure your classmates that you support opportunities for female athletes to participate in collegiate sports, but that you'd support a movement that encourages schools to spend real money to expand female athletic programs.