There's also a question of the strength needed to turn over those levers called arms. All things considered, a woman's commonly going to have a slightly shorter stroke/higher turnover than a man will because they don't have the same level of arm & shoulder strength to 'max out' the propulsion generation on each arm stroke.
Swimming is not rocket science; it's the interesting intersection between physics and biology. I can remember a discussion years ago with a coach about how butterfly is the fastest stroke from a physics standpoint (and why dolphin kick off the wall eventually became such an important part of pool swimming) but because of how the human body is built, you're just always going to fatigue quickly in fly compared to free, so you can never really use that maximum fly speed for more than about a 25.
Swimming is not rocket science; it's the interesting intersection between physics and biology. I can remember a discussion years ago with a coach about how butterfly is the fastest stroke from a physics standpoint (and why dolphin kick off the wall eventually became such an important part of pool swimming) but because of how the human body is built, you're just always going to fatigue quickly in fly compared to free, so you can never really use that maximum fly speed for more than about a 25.