Clearly, if a crystal ball is not an effective way of predicting the future, then ten crystal balls will be no better than one crystal ball in telling you next week lottery numbers. This also means that going to psychics and playing the lottery are unwise choices, but that must wait until another post.
Using this same logic, if one scientist makes a prediction that is not based on solid evidence, then having a large number of scientists agreeing with the prediction is no greater indicator that the prediction will come true. The important aspect about any prediction about the future is the available evidence that one is using for making such a claim, not the number of individuals that agree with you. Even if those individuals happen to wear white lab coats. It is important to remember that these scientists are not making scientific predictions - they are expressing their faith-based hopes. They are not looking into their microscopes for the data that supports these predictions, but instead are consulting their crystal balls.
For example, here is a letter given to Congress by the American Association for the Advancement of Science regarding the debate on embryonic stem cells:
The scientific consensus is that embryonic stem cell research is an extremely promising field of research that may lead to the development of more effective treatments for devastating conditions like diabetes, spinal cord injuries, and Parkinson’s disease.A mentor of mine likes to remind us that the absence of consensus does not mean the absence of truth. Likewise, simply because a certain group, with preconceived ideologies regarding science, agree on a faith-based idea, it does not indicate either a scientific truth or even a scientific theory.
Just like the crystal ball example, we should look at the history of such predictions especially in regards to the incredible cures that are promised "just around the corner" as long as we give them lots of money. The examples of predictions by scientists that have not panned out are numerous and easy to find. Every single time you read about a drug that needs to be recalled should remind us that there was a time in which the "consensus medical opinion" supported the use of the drug. Every so often we hear about a potential cure for cancer - yet even today our main strategy for treating cancer is basically unchanged for the past 40 years. We either cut it out or poison it.
This is not to say we should have a completely skeptical view - but we should pause and investigate when confronted with miraculous claims. We should look at the advantages and challenges of any form of medical research. We should not only examine the ethics of the practice itself but the future impact of that practice on humanity. The faith-based predictions of any number of scientists does not indicate science. Hope is good, but self-serving false hope is cruel, when it comes either from a crystal ball or the mouth of a "scientist".