Here is a pro-con speech sample discussing children and cell phones, and whether or not children having a connected mobile device is a good idea.
Either use it as a 'template' for writing your own pro-con speech or use it as a starting point to write a controversial statement on this subject.
To turn this into a controversial speech, choose an argument of value such as, "Children should not be allowed to use cell phones." Then use a pro-con discussion to support your statement. Of course, as youth having smartphones become ubiquitous, a more timely controversial speech topic might be children and augmented reality implants.
So what do you now think about children and cell phones? Should they be allowed to use them on a limited basis, or is your opinion that they should be forbidden to use them at all? Hopefully, this pro-con sample speech gave you an idea of how to go about writing one of your own.