Madonna is known for controversy and taking huge risks. Gaga also does it, but Madonna is the core of pop music controversy/risks. She paved the way for female artists to mix sex, religion, race, etc. into her music. Whatever risk is out there, Madonna knows she can take it and offend anyone by it, whether it be on purpose or not. Madonna is more grimy at taking risks. She doesn't exactly care if her music sells well, she is all about the risks and "why not's" in life. Gaga plays it safer and knows where to stop. Madonna is Madonna. Gaga is Gaga. Both take risks, but Madonna did it before it was "ok" to do so. She is the queen.