First of all, let me thank you for the entertaining gems sprinkled through this piece. For example:

Equations that prove whatever you want them to prove
and
White-clad people announcing that they found a growth is not usually good news

At some point in your essay I thought of marsupials. I did some Google searches and discovered the tammar. This mammal, native to Australia, has a growth curve represented by an "S" on a graph. It has an early spurt (in the pouch), a leveling off, another growth spurt, and another leveling off. This occurs in both sexes, and during the second spurt, rapid growth is also "seen in limb bones.". I know nothing about tammar endocrinology. Actually, I know nothing about tammars, except what I just learned. I just thought it was an interesting bit of trivia in light of your discussion.

Also, wildlife documentaries will never be the same for me :)