Aniel Callahan; The Puzzle of Profound Respect

Please fully explain the logic of the article written by Daniel Callahan; The Puzzle of Profound Respect Human embryo research(pages 372-375), and then explain where you think it goes wrong or where it is weak.

sidenote:
Please write it from my point of view. I do believe in embryo research but am against abortion. I am a woman who has been trying unsuccessfully to get pregnant for 15 years. I am currently in IVF treatments (and have been for over a year). I believe a baby is a living being when it has a heartbeat. You can detect a heartbeat with ultrasound at 4 weeks past conception. If someone dies when their heart stops, shouldnt life begin then?