"To persuade my audience that cloning human beings is morally unjustifiable" is a specific purpose statement for a persuasive speech on a question of value.

Your specific purpose statement, "To persuade my audience that cloning human beings is morally unjustifiable," indeed articulates the intention of your persuasive speech clearly. When addressing a question of value, you are essentially tackling ethical considerations, perceptions of right and wrong, and moral judgments surrounding a controversial topic.

In crafting your speech, it will be vital to provide a well-rounded argument. You should consider the following points:

1. Ethical Implications: Discuss the moral responsibilities involved in cloning. This includes the potential for exploitation, loss of individuality, and the implications for family and kinship.

2. Social Consequences: Explore how cloning could affect societal values, human relationships, and social structures. Consider the fear of "designer babies" and the alteration of societal norms surrounding birth and identity.

3. Scientific Risks: Address the scientific uncertainties and long-term health implications of cloning. Highlighting documented cases of cloning failures may strengthen your argument.

4. Legal and Religious Perspectives: Integrate viewpoints from various legal and religious frameworks that typically oppose cloning, emphasizing the consensus against it in many ethical theories.

5. Counterarguments: Acknowledge and refute opposing viewpoints respectfully. Discuss why the potential benefits of cloning do not outweigh the moral dilemmas it raises.

In summary, maintaining a clear ethical stance while being open to discussion will solidify your persuasive argument against the cloning of human beings.