How many offspring does a sperm donor create?

We put this to Wendy Kramer, Co-founder and Director of the Donor Sibling Registry:Well, the answer to that is a little bit tricky because nobody keeps track. What we do know is that the guidelines here in the US are supposed to be that only 25 pregnancies per 800,000 of a population area should be allowed for each donor. So that would mean that what they would like to do is limit each donor to 380 children. But the bottom line is, the sperm banking industry doesn't keep track. They don't have accurate record keeping. So they really don't know how many kids are born from any one donor.For instance, we have one donor on our site that says they donated two times a week for two and a half years. And this is pretty common. Each one of his donations turned into approximately 10 to 15 vials. So he produced over 3000 vials during that time. So just for that one donor, 3000 vials were sent out. But we don't know many children were born from those 3000. You could say, maybe up to 3000, but we don't know. What we do know is that on our website we have very large groups of half-siblings. They're people born from the same donor. Many in their 20s, 30s, 40s, 50s, with the largest group that we know being just over 125.