[gwern]

We know that whatever damage is caused, it can't be too bad because children born using sperm donors - which can be frozen for storage - don't have increased defect rates, but have decreased defect rates, something like 1/5

/checks http://www.gwern.net/Ethical%20sperm%20donation for his old citation

Yes, 1/5 according to http://en.wikipedia.org/wiki/Sperm%20donation%23Sperm_donati...