I think the only way to really compare this is with the elite runners – males and females that have been running and training to win for many years.
This is precisely what I'm talking about doing.
But there are too many variables – even with the same coach – the coach will likely not give them the same training effort, use the same techniques with them etc . .
That's true with all athletes, regardless of whether or not they are of the same gender. It's all about building the program around the individual and not trying to make the individual fit a program that may not be ideal for that individual.
There is some results based evidence of something going on – Has the time gap been the same for several decades or is the time gap closing?
It has been closing to some extent but I've seen the world record progression curves for both men and women for many different events. Those curves, regardless of distance or gender, follow very similar trends and show that the men do have a distinct advantage.
The progression curves I've seen have been in books but, when I get a chance, I'll see if I can find any of those online.