A particularly interesting and convoluted argument as to why my donor doesn't matter consists of two parts:
1. When you were a child, your legal parents had the right to define themselves as their parents for you and were thus your parents, and so you didn't lack anything, and you didn't know, anyway, and
2. Now you're an adult so you don't need a father any more. What would you want from him now, anyway? To buy you ice-cream and tell you bedtime stories?
So, before, it was too early; now it's too late.