This PPT goes through several key Christian teachings on beginning of life issues. It attempts to consider both the pro-life and pro-choice perspectives. There are areas of discussion throughout as well as some opportunities for stretch and challenge for the very brightest students. For example the syllogism is used here to demonstrate both sides of the argument.
There is also a lead into the required scholar, Peter Singer - I set this as a further reading task but you could add the information if needed.