Chris, I agree with Paul in regarding the sensitivity that's a matter of proper aikido training not really a result of being physically strong. Someone can be very weak or very flexible and still not be sensitive to their partner. But, Paul, I do have to say that someone very strong and who does not have proper aikido technique is more prone to injuring a partner more so that some one who is not strong because they can more easily muscle through their techniques. But that, again, goes to someones aikido skills rather than the fact that they work out.
In regards to the testosterone, many women don't work out with weights for a similar reason thinking they will bulk up like a man. Well, what they don't realize is that women don't have nearly the amount of testosterone as a man so we just don't bulk up like that, UNLESS, steroids are invovled. I guess the same is true with men on a different relative scale.