Okay, so Bernard Nathanson was a man who worked as a doctor a long time ago. He helped to start an organization that helped women who were pregnant and didn't want to have a baby. The organization was called "National Abortion Rights Action League," or NARAL for short.
However, as time went on, Bernard Nathanson started to change his mind about abortion. He began to see that it wasn't just a choice for women, but that it meant taking the life of a baby. He felt really bad about all the babies that had been aborted because of his work.
So, Bernard Nathanson started to speak out against abortion and even made a movie called "The Silent Scream" that showed ultrasound pictures of a baby in its mother's womb. He wanted people to see that babies are alive and need to be protected, even before they are born.
Because of his work, many people began to see that abortion wasn't just a choice, but that it involved a human life. Bernard Nathanson was a person who changed his mind about something really big and helped to make the world a better place for babies.