Jennifer Matthews: These tiny pills are stirring up a hot debate. Some experts say they could cut abortion rates in half. Others say they are abortion. Dr. Omar Hamada: The egg and the sperm have met and created a baby. That is an abortion, essentially -- a medical abortion. Jennifer Matthews: But Dr. Jeff Andrews says it depends on how you define abortion. The U.S. government says abortion is terminating a pregnancy after the sperm and egg have met and that fertilized embryo has implanted in the uterus. Plan B prevents implantation from ever happening. Dr. Jeff Andrews: Plan B could not possibly be an abortive fashion because it acts before implantation and does not affect the pregnancy after implantation. That's been proven. Jennifer Matthews: Safety is another issue. Dr. Hamada says easy access encourages frequent use and could pose risks we don't know about, like ovarian cancer or infertility. Dr. Omar Hamada: We don't give people open access to antibiotics or other things like that for similar reasons -- just because people would tend to take them way too much, and that causes problems. Jennifer Matthews: Dr. Andrews, says studies show even when women have easy access, most only use it in emergency situations. Plan B is very safe if used according to instructions. Jennifer Matthews: Med student Sara Risner-Adler had an emergency and was able to get Plan B in time. But many of her friends haven't been as lucky. Sara Risner-Adler: People had oftentimes have said, 'Well, I really should have taken it, but I could not get it, and let me just cross my fingers and hope. Jennifer Matthews: But now you can get it -- and whether it's a step in the right -- or wrong direction -- is for you to decide. This is Jennifer Matthews reporting.