Why can't you donate blood if you have had an hcg(?) shot?

Question

It was explained to me somewhat by the red cross lady at the bloodmobile, that you can't do it because the hcg &hgh are made from human brains (EW) but.....if the person whose brains they were made from was unhealthy, they wouldn't have used them in the first place, right? Why would it even matter, especailly if it was over 10 years ago? The shot wasn't benefitting to me, it was done as part of the fertility treatments for an egg donor program where I gave my eggs to a fertlilty program at a major hospital.