A theory is only good as long as no contradictions have appeared. If they do, the theory falls apart like a dry cookie. This has happened countless times in the past, and will happen in the future as well. Every time a important discovery is made, it questions the things we believed to know about that subject before. A good example is the theory about the age of the world. It has been revised a dozen times in the past 300 years - from 7000 years in steps to 4,5 billion years now. But it's a normal process, we only have to start worrying if we think that we have solved all questions.
There are no contradictions to a scientific theory. That's what they mean by theory. If you mean scientific beliefs, I guess there was the belief during the Renaissance that women didn't contribute to their children's heritage at all.