Now before you get all pissy about this....think about the focused, centered power of bearing a child...it is incredible...never having felt this I can see where some men and some women who have not had children can doubt the power of softness, determination, nature and focus.
I'm sure bearing a child is a feat that would make most men cry, including myself.
But for anyone that has a modicum of these skills would also know that the statement you made is basically comparing apples and oranges.
Internal skill comes from rewiring how you think and move, but is also dependent on conditioning. Lose one or the other and you'll always lose out on these skills. Anyone with decent internal skills had a tremendous amount of certain physical conditioning, whether it be Ueshiba, Shioda, or Tohei etc.
(All you have to do is take a look at Ueshiba's near nekkid figure when he was doing misogi to see the tell-tale signs of that physical conditioning.)
Who knows, maybe Ueshiba got his stuff from visualizing having birth