our child because we think they have a right to know their "story" so to speak. We also figure that telling takes the potential wind out of the sail. Secrets can become mysterious and glamorous. The truth is a lot less, well, mysterious and glamorous. Also, we think that should our child happen to find out in the future by accident, it would probably happen during the worst possible time - during a crisis or during adolesence. And asking a person to decouple the concept of motherhood from genetics during such a time is a lot to ask of someone.
As for family - we are telling only my mother, brother and two friends. We need some emotional support during this process and they provide it. They also are discreet and can be trusted not to share. I'm not even telling my best friend, because she cannot be trusted not to tell her entire family. If our child wishes to share more broadly in the future - that will be their decision. Our child should not be the only person in the room who doesn't know, is our thinking. Again - their story.
By the way, we are doing a semi-open donation as well.
It is a very personal decision and people have good reasons for deciding one way or another. That's just our thinking.
Good luck with the process!