af·fir·ma·tion n.
1. The act of affirming or the state of being affirmed; assertion.
Right, to get him to give you a personal letter, something he doesn't have to to at all and only does to people he knows, likes, and wants to help personally -- you have to make an assertion about how you believe the human species originated.
If he doesn't like your assertion, he doesn't have to write a personal letter.
And the problem is?
That's a nice definition. Here's another one.
affirmation - (religion) a solemn declaration that serves the same purpose as an oath
I see an affirmation as an oath, you see it as a simple assertion. I think 'assertion' is a very weak replacement for an 'affirmation'.