I'm hashing out a new story idea for a rom com that is going to require some research into dysfunctional relationships. If I research primarily from one or two books, is that considered an adaptation? Normally I would laugh at this sort of question, but a recent trend has me wondering. "He's Just Not That Into You" was "adapted" from a self help book. I've never read the book, so I'm not entirely sure how they compare. Were they just paying for title recognition? Even more recently, I read that "What to Expect when You're Expecting" will be adapted. How do seven plotlines centered around pregnancy and parenthood become an adaptation? If that doesn't just count as simply research anymore, is everyone going to be expected to have options on their primary sources?
No. In both these cases, producers are buying the property in order to be able to sell the property, and the title, to a studio. "I've got the rights to the most famous book on childbirth" gets you a meeting or two.
But as a writer you can certainly write stories based on nonfiction all day long. By the time you're done making up stories, it is unlikely anything will remain of the original copyrighted material. (Make sure it doesn't.) So you're free and clear. You can even tell people it's "inspired by books like WHAT TO EXPECT..."
You can't copyright an idea. You can't copyright biology or culture or sociology. You can only copyright the specific representation
of an idea. Which means I can do an awful lot with your idea before I have to option the rights from you.