<human>: Can you give me the gist of the text in a nutshell?

This evening my boyfriend of 5 years came home from work with, what he called, exciting news. He said his boss had asked him to be a sperm donor for her and her wife. 

Important information moving forward:

It will be artificial insemination.

There will be a legal contract that          
relieves him of any duty to the ladies or the child. But he has the option to be "Uncle" if he so chooses.

He had put in his two week notice at work today, as he's been accepted as a trade apprentice.

The process could/would take several months.

The ladies have offered to have us over to hang out so the situation is less awkward (I'm not quite sure awkward is the right work here, ha.)

He's asked me not to share this with anyone we know.

    My first gut reaction was: RIGHT ON!! I mean, what an amazing opportunity! After asking him some questions and having a second to think it over I find myself conflicted. I am inclined to chalk it up to basic human selfishness, though. 
I'm by no means ready to have kids of our own, but I hope one day to explore the idea. I am so happy that he can help this family grow but then I think his first child will not be with me. In the long run, that really doesn't matter yet somehow part of me feels like it may tickle the back of my mind for a long time. 

   Another thing is that they offered him compensation, but how do you put a price on the gift of life. While it's not my decision I have expressed that I hope he doesn't ask them for money at all.
I guess my real reason for posting is I'm just a little mind-blown with the whole situation and I'm looking for other perspectives to help me ponder this point in my life.
<bot>: I feel weird emotionally about this situation though I am 99.99% for it. How would you feel in my spot? I need some perspective.