According to Engber[‘s article], Human Growth Hormone (HGH or GH) has little to no performance enhancing-benefits. … I have the benefit of working down the hall from several exercise physiologists.  I forwarded [his] article to my colleague, John McLester. … “Oh yeah, I agree with [Engber]. This isn’t even controversial in exercise physiology. … There is no evidence of [benefit from bigger muscles]. It seems that the muscle that is developed is abnormal and not mature. I’ll point you to some studies (see below). …

With [Major League Baseball]’s adoption of mandatory testing for steroids, many thought that home run rates would drop dramatically. They didn’t, and many felt that the lack of a test for HGH could be part of the explanation. Well, it’s time for the scientists working on such a test to start something else more important.

That is John Bradbury.  He interprets:

The illegality of growth hormone actually promotes its use in sports. … The banning of a drug by anti-doping authorities sends a loud and incorrect signal that it works. … Therefore, I believe that legalizing growth hormone is needed to send the signal that it doesn’t work, largely to undo the widespread common belief that growth hormone does improve performance. … Think of the powerful effect it would have if MLB pulled growth hormone off its banned list. I can’t imagine a more powerful signal of a drug’s lack of potency as a performance enhancer. If we are going to be paternalists, let’s be effective paternalists.

Added 5Mar: See also here, HT Tyler.