Complex sentence: Lee broke some of the stereotypes by demonstrating that they could be tough and masculine, but in opening new doors, he created new stereotypes-that all Chinese men know Kung Fu or other forms of martial arts.
Split into simpler sentences: Lee broke some of the stereotypes by demonstrating that they can be tough and masculine; but in opening new doors, he created new stereotypes. This time, the stereotype was that all Chinese men know Kung Fu or other forms of martial arts.