I think you're missing the point of what I'm saying. It's not about having an older doctor, but rather having a doctor that looks the part. The actress could be the same age as this one and look more mature in her role and more believable in it, and that wouldn't skew demographics in the least. As it is, they cast an actress that looks far too young regardless of what her age is or what the demographics are, and that's simply bad casting. The right casting can make a great deal of difference in how we perceive things, particularly when it's the lead role, as everything else can fall apart if the lead role isn't believable.