> Then again, it might be hard... You've answered your own question there. As I understand it, pregnancy and childbirth related studies often have this issue a

> Then again, it might be hard... You've answered your own question there. As I understand it, pregnancy and childbirth related studies often have this issue as the moral stakes are higher and there are issues around consent. Also under normal conditions neither is actually a medical condition/procedure which needs treating and the benefits are often only seen over a long timeframe, making obtaining volunteers less straightforward. As long as everyone is honest, less than perfect science is still useful.