My wife and I were discussing (arguing a bit) over this case last nite.
I liken this to contract law.
Man and woman engage in act. If either party clearly stated in advance that desired outcome was no child, and other side agreed to same, then it seems that someone -- in this case "woman" -- clearly broke the original contract.
If woman had indicated at the time the contract was engaged in that she wanted to concieve a child, then man would have had opportunity to not enter into the contract.
Given the details as described in the article, it seems clear that the guy had no reasonable expectation that the raw materials he provided were going to be used to create a finished product. He believed he properly disposed of those materials in a manner that would not result in any further use of the materials. Unfortunately, woman seemed to have had other plans -- including seeking support for the product which was created.
I can imagine a case like this being discussed for years in Harvard law. Too bad Professor Kingsfield isn't around to teach it to his favorite student, Mr. Hart.