confusing usage of prepositions

There are two confusing examples of preposition usage. Both - from IMDb site (the Internet Movie Database):
1. 'She has two children BY Tim Robbins...'

The 'by' in this context seems odd to me. BTW, is it possible to use the same 'by' talking about Tim Robbins? He has two children by Susan Sarandon...
2. 'Biography for Susan Sarandon'

It doesn't sound as strange as 'has two children BY' does, but why not 'Biography OF'?

For item 2, I think you could say either "Biography of" or "Biography for".