This is one of the most twisted stories ever. Details available here: Sperm: Court dismisses man's theft claim against lover who kept semen, or through these Google results.

What it basically boils down to is a man and woman had a an affair 6 years ago. Affair? Yes. Sexual intercourse? No. But she did perform oral sex on him, and afterward she saved the semen (without telling the man) and used it to artificially inseminate herself (again, without the man's knowledge). She was successful in impregnating herself with his semen, and eventually gave birth to "their" child. Two years would pass before the man found out he was a father, thanks to the woman filing a paternity claim against him. DNA tests confirmed that he was the father, and basically he's been forced to pay $800/month in child support to this lady for the past 3 years (and probably for the remainder of the kid's life).

It is absolutely stunning that the courts upheld her side of the story, saying that the semen was "a gift, an absolute and irrevocable transfer of title to property from a donor to a donee." This entire thing is just wrong.