Maybe you did it for the extra cash. Maybe you wanted to be part of the sperm cube public art project. Whatever the reason, it's possible, just possible, your sperm took on a life of it's own, once you left it.
And now that a genome is no longer an entirely personal bit of information, you may be in for a surprise meeting someday, with the end result.
Male adoptees are getting their DNA tested and getting information about their possible surnames.
According to the BBC news:
At least 30 men registered with US consumer genetic testing firm Family Tree DNA have found their "biological surname" in this way, the company's chief executive told BBC News. The company has an online database called Ysearch containing genetic information from 125,000 men, along with surnames and other genealogical data.
As yet, I don't think there's anything that protects a sperm donor from a lawsuit from a child, claiming to need, oh help with college expenses, or just whatever.
It might be something that you want to look into.