I was told that the mothers were able to choose from a catalog which donor they wanted to use-- they listed things like race, ethnicity, occupation, height weig

I was told that the mothers were able to choose from a catalog which donor they wanted to use-- they listed things like race, ethnicity, occupation, height weight etc. So I suppose that some donors were used more than others. A lot of us siblings live in the same area so while its conceivable that inbreeding is an issue, it's probably like a 1 in a few million chance that you meet a sibling randomly.