How soon can you hear the baby's heart beat?
With an ultrasound, at about 3 or 4 weeks. With the device the doctor uses in the room, at about 9 weeks. I don't know for the things you buy at the store.
I am going to disagree with this last answer. With a vaginal ultra sound a heartbeat can be detected as early as 6 weeks gestation but more commonly by 7-8 weeks gestation. Of course she could be right and we are just counting the weeks differently.
With my first child my Dr. could hear my son's heart beat at 7 weeks with out a ultra sound and now being pregnant with my second child and having the experience in a medical setting working in a OB practice I have heard my baby's heart beat at 5 weeks and 3 days.