Excellent question my dear sweet Cryssie Poo! (yes new nickname, you have reached a new level)
Men and women have a power sharing relationship than forms the basis of our society. Men are obviously physically stronger but women's strength, physical and otherwise, perfectly compliments men's.
Women allow men to think we're stronger all the while maintaining more strength in more subtle ways. Women can influence men to be bigger, faster, stronger, smarter and better than we would normally be. That takes emotional and mental strength.
Men may fight wars, sail the seven seas, climb Mt. Everest but we still need a home to come to. Women can do all that exciting stuff, but maintaining a home and having kids take a special kind of strength.
Really one sex isn't stronger than the other. Ideally, our strengths fit together to make each other, well, stronger. 🙂