Great Britain appears to be suffering from a shortage of sperm donors:
I can't imagine what it's like to not know a father's identity, and applaud anything that gives people the choice of finding their biological fathers.
The rules also seem to make it possible for siblings seeded by the same donor to find each other. And while one wouldn't need to choose between finding siblings or a father, I'm fascinated by a hypothetical question: if your father was a sperm donor, who would you rather know -- him, or your brothers and sisters?
Clinics fear sperm shortage as anonymity ends [Scotsman.com]