An amazing exchange from a parent and (unrelated) donor on the Donor Sibling Registry Yahoo Group that I received permission to share here:
From a parent:
There are a few donors on this board who I’ve come to admire and
respect and I’m hoping you will step forward and answer a question
that I have been pondering for some time. My 13 year old son and his
donor met and became fast friends back in June of this year. They
share many of the same likes/dislikes, have many of the same
personality traits/tendencies and truthfully, look more alike than
most fathers/sons do. My son had often wondered who he looked like,
and only had to look in the face of his biological father to have that
question answered. My husband and I both agree, that they most
definitely have what we refer to as a “cosmic connection”. And no, my
husband has never felt “threatened” by our son’s relationship with his
biological father. Just thought I’d throw that in because I’m sure
some of you are wondering about that. 
I must admit to questioning though, why there are donors who, like
ours, want to become part of their biological offspring’s lives. If
there are any donors out there who would be willing to answer this
question, I would very much appreciate it. Thank you
A donor replies:
Speaking for myself, I probably have several reasons for wanting to
make contact. I think first and foremost was just plain and simple
curiosity. I think it’s kind of a guy thing. We tend to want to see
how we measure up. When a little boy puts wood and cinder block
together for the first time to make a ramp, and then finally musters
up the courage to hurtle himself over it on his bike in front of his
friends, the first thing he wants to know when he lands is how far
he jumped…
I guess there was a degree or altruism from the start though. I
mean, yes, I was in college, and I liked the extra cash, but after a
while, when I really thought about what I was doing, I kind of felt
good. And that was the start of my initial curiosity. The real
altruism came later when I got married and became a father myself.
Children change our lives. It was at that point that I could really
understand how important it was for people who were having problems,
to be able to become parents for the first time.
After that, I would call the donor clinic where I had been a donor
years ago to let them know about my own children, and how they were
doing, on the outside chance that one of my donor children’s parents
might want to be able to gauge how their child was doing. It was at
the point of parenthood for myself, long after the money was gone,
that the whole meaning of what it was to be a parent made sense.
I want all my genetic offspring to be happy and healthy like my own
children. I will always love them and wonder were they are, what
they are doing, are they living, learning and experiencing life like
me and my own children? I hope that they are bringing the same joy
to the lives of all the mothers and dads the same way my life has
been enriched by my own children. We are, and will always be,
connected. Some of them will become equally as curious as I was some
day, and want to know more. I think we owe it to them to let them
learn.
I admire your husband. He is obviously a secure man who has no
worries. That comes from providing a child with a “home” full of
love, care and respect. He has no problem because he knows that he
is, and will always be, Daddy…this other guy might be the father,
but it’s Daddy who makes the difference in a child’s life. In the
same fashion, the child will always, only ever be, a genetic
offspring, and that’s the way it should stay.
I don’t have a problem making a connection (I just made my first a
couple weeks ago), but it needs to be done correctly, and for God’s
sake, all you other mom’s thinking about this need to know that it
needs to be done in an open and positive manner. Children look to us
to know how to react to any situation that they are unfamiliar with.
Be safe, but if you decide to make a connection, be positive, open
and honest at all times.
So, in answer to your question, I think there are many reasons a
donor father might want to get involved with a genetic offspring. I
think though that those reasons change over time as we grow older
and wiser.