[Puddleglum]

Using the same logic, every sperm bank donor would be responsible for some unknown number of children

Exactly. That's why I called it fast-food fertility. Donors to sperm banks know their sperm is intended to create children. They are knowingly entering into the business of parenthood.

[elfman2]

”Donors to sperm banks know their sperm is intended to create children. They are knowingly entering into the business of parenthood."

Unless they were informed of a precedent invalidating their donation contracts (which they weren’t because one probably did not exist) then they “knowingly” entered into nothing of the kind.