Clinical decisions in reproductive medicine are often made in uncertainty. To reduce uncertainty and to improve clinical decision-making, RCTs are increasingly called upon. A key concept underpinning the ethics of RCTs is equipoise. Here, we aimed to dissect the basic reasoning behind the concept of equipoise and we proposed a line of thinking delineating under which conditions it is ethical to design and execute an RCT. This might prevent a priori negative trials, reduce research waste and aid in the design of meaningful ones. It is these trials that will provide insight on how to safely and effectively assist subfertile couples.