Yes, I do think that Placebo-controlled trials are both ethical and necessary. When performing any scientific study, I think it is very important to have a control to be able to compare the effects of whatever it is you are studying (medication, treatments, etc.) to someone that has not received these medications or treatments. Having a control gives you the ability to see what would happen to your samples or patients if the medication or treatment was not administered. In my opinion having a control allows you have more accurate data instead of assuming what the results of a controlled sample or patient would have been. I do not see many disadvantages with having a control, besides the additional amount of money it cost to include the extra control patients in the clinical research study.