That was decades ago though. AFAIK nowadays all countries operate large banks - the UK has a big one. It s likely that a donor CAN be found through such banks. Besides, this kind of commercial approach is not systematic and doesnt guarantee diversity of samples in any way -- in fact people from economically disadvantaged genetic backgrounds will have less access to it. Diversity is somethign that public bases do take into account.

Why do you think they'd have less access? They have greater access because they will 100% find a donor - themselves. It guarantees access to a sample regardless of genetic background

As I understand it many of the common potential use cases only work if you have a donor who isn’t yourself. Because if you have a genetic disease that disease will be present in your stem cells. The most common example I’ve heard is of storing stem cells to help a potential future sibling, not the baby directly. Or am I mistaken?

It has been used for the baby themselves & siblings :)

Some cases where babies use them themselves: https://www.nature.com/articles/bmt2012146

https://pediatrics.duke.edu/news/umbilical-cord-blood-improv...

I understand that it happens, my question is the prevalence. When I looked into banking cord blood I found a lot of ‘possible’ and one-off cases, but no actual statistics about how likely it was to be useful. That made it unpalatable, especially compared to the known benefits of delayed clamping.